Make It Fizz!

Make It Fizz!

By: Jeff Shoemaker 

This article originally appeared in the 

Jun/Jul 2019 issue of Winemaker Magazine 

 

Making non-traditional sparkling wine at home through force carbonation is simple and can yield amazing results. With just a few pieces of equipment, one can make delicious bubbly in a matter of weeks. In this article I will outline how to keg, carbonate, and bottle sparkling wine to be enjoyed with friends and family.

Force carbonation is done by injecting carbon dioxide (CO2) into a solution (up to 50-60 psi), as is the common method of carbonating soft drinks, sparkling water, and often beer. Even though we are not reaching traditional champagne psi levels (75-99 psi), it is the best we can do with readily available equipment. By racking wine into a keg, refrigerating it, and connecting the keg to a CO2 tank set at a specific pounds per square inch (psi), over time, results in the wine becoming saturated with Co2 and turning into sparkling wine. There is more to it, but this is basically the process.

Required Equipment

Before you get started, I must warn you that you will be working with contents under pressure. Be sure to wear protective clothing, and eye protection. Keep children away when handling pressurized kegs, especially when bottling. Wine could spray out or bottles can fail during the bottling process. Tell those kiddos to go play some Fortnite.

List of Needed Equipment

• 5-gallon (19-L) Cornelius keg and necessary connections

• Co2 tank and regulator

• Refrigerator

• Stainless steel counter pressure bottle filler with pressure gauge

• Hoses and tubing

• Bottles for carbonated wine: Champagne, flip-top, or beer bottles (if bottling under 50 psi)

• Bottle closures (crown caps, Champagne corks and wire, or plastic stoppers)

• Bottle capper or Champagne wire tightener tool

Let us briefly break down each piece of equipment so we can familiarize ourselves with them.

Keg

Cornelius kegs are the most popular kegs for carbonating wine and beer at home. They come in various sizes, but most common are 5-gallon (19-L) kegs, which can hold about 25 750-mL bottles of wine. They are readily available from local and online homebrew outlets and can usually be found used and at a discounted price. There are two different kinds: Pin lock and ball lock. Pin and ball simply refers to how the connectors will attach to the keg. Ball lock is a quick-disconnect style and the pin lock actually has pins on the post to secure the connector. Within each post is a spring-loaded pin called a poppet. Within each black and gray connector is a pin that will depress the poppet to allow gas to enter the keg through one and liquid to come out through the other. Another difference between these kegs are their height, with 5-gallon (19-L) pin lock kegs measuring at around 22 inches (56 cm) tall and ball lock kegs approximately 25 inches (63 cm) tall with another ¼- to ½- inch (~1-cm) added to each for the connectors. Be sure to measure the height of the inside of your fridge to ensure a good fit. Each keg is equipped with a pressure relief valve that will allow excessive pressure to escape in the event the keg is over-pressurized. The pressure relief valve on the ball lock keg has a pull-ring and can be engaged any time whereas the pressure relief on the pin lock can only be engaged when the pressure exceeds 130 psi. No matter what keg you choose, either keg style will do the job just fine.

Co2 tanks

These can be rented at local welding and gas supply outlets for a fee. If you plan to make sparkling wine production a part of your yearly wine making practices, the less expensive option, in the long run, is to purchase the tank and simply pay to have it refilled or exchanged as needed. A 5-lb. (2.25-kg) tank will do a few kegs before needing a refill. Choose the size that fits your output.

Dual Gauge Co2 Regulator

These can also be purchased from welding and gas supply stores, although purchasing online may be a less expensive option. These regulators have two gauges — one tells you the approximate gas level in the tank and the other informs you of the current psi level in the tank. The psi level is adjusted either by turning a knob or a screw with a flat-head screwdriver. Most regulators go up to 50–60 psi.

Refrigerator

Co2 is absorbed into wine more readily at lower temperatures. To avoid wasting Co2, be sure to cool the keg of wine first before beginning the carbonation process (more on the later). Depending of your desired setup, you could use a spare fridge or a kegerator — just be sure the height allows for the size of your keg.

Counter Pressure Bottle Filler

These are hand held units that fill Champagne and beer bottles under pressure, free of oxygen exposure. You will see a few different versions for sale online. Since we are bottling wine, only a stainless steel bottle filler should be used. I recommend the bottle filler with a pressure gauge so you are aware of the pressure while filling.

Please Note: Only Champagne, flip-top (E.Z. Cap bottles), or beer bottles suited for bottling carbonated beverages should be used as they are made to withstand pressure. Be sure not to exceed the maximum pressure in order to bottle safely and securely. Remember to always wear personal protective equipment when bottling your carbonated beverages.

• Beer bottles: 50 psi

• Flip-top or E.Z. Cap bottles: 58 psi

• Champagne bottles: up to 90 psi.

Which bottle you choose should dictate the psi level you set your tank to in order to carbonate it. I usually go a few above the recommenced psi level because I am assuming I am losing a few psi in the bottling process.

What is a Good Wine for Force Carbonation?

The Answer: Anything and everything! What is great about kegging and carbonating wine is you can take a single gallon (4 L), carbonate it, and determine if sparkling is a good fit for that wine. I prefer to carbonate sweet wines that I make such as black/red raspberry, Catawba grape, cranberry, blueberry, and many others. One thing I have learned is that carbonated sweet wines will taste dryer than their still versions. This is because some of the carbon dioxide turns into carbonic acid and contributes to the overall acidity of the wine (think of a wine that has not been degassed). This is something to consider when back-sweetening a wine before it goes into the keg. You may want to bump up the sweetness level just a bit. Be sure to experiment to nail down your usual suspects you will carbonate every year. Documentation is key to future successes. Rather than relying on your memory for sweetness levels, psi levels etc., write it down and refer to it later.

How to Carbonate: Step by Step

1. Ensure your base wine or cuvee is enjoyment ready. This means clear, stabilized, and ready to drink. The wine will not develop any further once in the keg and shut off from oxygen forever.

2. Sanitize everything.

3. Rack the wine into the keg. Stop filling once the wine has reached just below the gas-in dip tube. This is so if there is any negative pressure, wine will not be forced through the gas line back into the CO2 regulator potentially ruining it (it has happened to me).

4. Close the lid making sure it is properly seated.

5. Connect the keg to the CO2 tank and set it to 30 psi allowing gas to flow into the tank (remember the gray or white connector is for the gas-in post and the black is for the liquid out post). Once the sounds of the keg filling with CO2 subsides, remove the gas-in connector to the keg and slightly depress the poppet in the center of the gas post (Pink-lock kegs) or pull the pressure relief valve (Ball-lock kegs) to release the gas. By doing this you are purging any oxygen from the keg. Repeat this a few times and then finally allow CO2 into the tank without releasing it. As you wait for the gas to flow into the keg, spray the lid and posts with Star San or other no-rinse sanitizer to check for air leaks. A leak is indicated by bubbles forming where Star San was sprayed. In the event of a leak, tighten the posts or release the gas and seat the lid once more. It also helps to spray around the regulator and all gas connectors to ensure there are no leaks.

6. Refrigerate the keg down to 32 °F (0 °C) over night. Cold temperatures allow the CO2 to saturate the wine more effectively.

7. The next day, connect the keg to the CO2 and set the psi to 55–60.

8. Allow the CO2 to saturate the wine for up to two weeks.

9. After two weeks has passed, the now sparkling wine should be ready to bottle. Or, if you would like to serve this wine on tap, initially carbonate the wine to around 15 psi. At this low pressure level, the wine sparkling wine can be served from a stainless steel tap faucet (chrome plated brass will degrade from the acidity in the wine). .

Bottling Procedure

1. The stainless steel counter pressure bottle filler comes with set-up instructions. Follow those to get the unit set up and ready to fill bottles. Be sure to chill everything (wine and bottles) prior to bottle filling. The tubing and filler will cool down from the wine flowing through them, but you could even chill those things too. Warmth causes a loss of carbonation as well as foaming, which we would like to do our best to minimize.

2. Practice using the bottle filler first to gain an understanding of how it works. Practicing with water is fine, just know water is not a highly carbonated beverage and when it is showtime, the bottling procedure will be a little different. Your first time may be a mess of sprayed wine and half filled bottles. This is part of getting used to using the counter pressure bottle filler. A rite of passage if you will.

3. Place the keg of wine in an ice bath to keep it cool. I fill my bottles in a dish tub to catch foaming and any spray that may occur (and it will).

4. Sanitize everything

5. Release the gas in the keg, reconnect the CO2 and set it to 15 psi and allow it to fill the tank.

6. Place the bottle filler wand into the bottle and secure firmly by pushing down, ensuring the rubber bung makes a tight seal. Once the Co2 enters the bottle, the bottle filler will want to push out to some degree. Do not allow that to happen as foaming will result.

7. Engage the 3-way ball valve on top to fill the bottle with CO2, engage the pressure relief valve on the side of the bottle filler to allow oxygen to be purged out of the bottle for a few seconds.

8. Close the 3-way ball valve and the pressure relief valve on the side. Turn the ball valve to allow wine to flow into the bottle. Wine will not enter the bottle until the pressure relief valve to opened to allow CO2 to escape. Do this slowly until the wine starts to flow into the bottle at a moderate rate, making sure foaming is kept to a minimum. Excessive foaming takes time to dissipate, prolonging the bottle filling process. Open the pressure relief valve more to increase the flow of wine and close it to slow the flow of wine into the bottle. The relief valve will need to be managed to address any excess foaming as the bottle fills.

9. Fill the bottle to the top. The fill level will be perfect once the pressure filler has been removed.

10. When the bottle is full, shut the flow of wine off with the 3-way ball valve. Slowly unscrew the pressure relief valve, not all of the way, but just enough to allow excess Co2 to escape and the pressure gauge on the filler goes down to under 5 psi.

11. Remove the bottle filler and apply the closure immediately. If using a plastic stopper, insert it into the bottle (placing the bottle on a wood block and using rubber mallet works well), secure it with the wire hood and insert the wire tightener tool to pull the wire tight, ensuring the wire is under the lip of the Champagne bottle. Twist six half-turns, creating a loop. Bend the loop up or down and then a foil wrap and a label can be applied for decoration.

Now that the bottles are filled and the closures are in place, they can be kept at cellar temperature on their side or upright. When you decide to enjoy this wine with friends, be sure to use Champagne flutes as that will display the bubbles beautifully.

An easier alternative to the hand held counter pressure bottle filler is Williams Warn Bottle Filler. It is countertop positioned, hands free, does not foam, and does not lose carbonation. Consider this if you really ramp up your sparkling wine production at home.

As you can see making sparkling wine at home with the force carbonation method is simple, and gives you excellent results. With just a few pieces of equipment, you can now add more diversity to your cellar and have something different to share with family and friends.

For a short read of my first experience with the counter pressure bottle filler check my winemaking blog post “The Counter Pressure Bottle Filler. A Bloody Mess Ensues” at http://ponivineyardandwinery.blogspot.com/2017/06/using-counter-pressure-bottle.html

Working with Small Barrels

By: Jeff Shoemaker

This article orriginally appeared in the

Apr/May 2019 issue of Winemaker Magazine

Oak wine barrels are a valuable addition to any winemaking set-up. Not only does a barrel add complexity, aroma, and tannin, it also allows a gradual, controlled amount of oxygen through the wood staves, which results in reduced astringency and helps stabilize color (among other beneficial phenolic reactions that increase sensory properties of the wine). When we compare our home winery to that of a professional one, we see that our home operation is a miniature version of the big guys, and the barrels we use are often no different. Using small barrels is perfect for home winemakers seeking the benefits of oak but not making enough to fill a 59-gallon (223-L) behemoth. In addition, their small stature is manageable, meaning you can pick them up and carry them around for cleaning (empty of course) and their footprint is smaller, which is a positive attribute in a home winery setting. Batches made at home are typically in the 5- to 15-gallon (19- to 57-L) range. Barrels at these volumes are very affordable compared to their 59-gallon (223-L) counterparts (have you ever priced a 59-gallon (223-L) French oak barrel? Gee wiz!) However, with the benefits of using a smaller barrel come a few challenges we need to overcome in order to take full advantage of what they have to offer. In this article I will attempt to alleviate any concerns you may have of using smaller sized barrels. I will go over how to prepare for your new arrival, how to break it in, and go over other things we will need to consider to get the most out of this new addition to the winery.

How to Choose a Barrel

Each type of barrel comes in several different sizes to accommodate virtually any volume being produced. Therefore, when thinking about what barrel is right for you, one must consider the different flavors and nuances a barrel provides and worry about the volume of the actual barrel a little later. There up to 400+ different species of oak and only a few are considered fit for wine barrels. Of these few, two types are grown in the six main forests of France known for oak: Limousin, Vosges, Nevers, Bertranges, Allier, and Tronçais. It is in these six main forests of which Quercus robur, known as pedunculate or English oak, and Quercus petraea, known as Sessile Oak are grown, with the latter being considered superior for its tighter grain and contribution of beneficial aromatics, phenols, tannin and volatile aldehydes. Hungarian and Eastern European forests also produce Quercus robur and Quercus petraea in the famous Zemplen forest of Hungary, with barrel oak also coming from Romania and Croatia. And last but not least, American oak (Quercus alba) which is grown in the eastern United States, Missouri, Minnesota, and Wisconsin. Each type oak has its own flavor profile and oak flavor transfer rates. French oak tends to add dark chocolate, roasted coffee beans and exotic, savory spices, with a subtle and slow extraction. Hungarian oak lends vanilla, spice and caramel-like flavors. Although Quercus robur and Quercus petraea are grown in both France and Hungary, it is the terroir that sets the barrels from each location apart. In my research I have found the trees grown in the Zemplen forests with its volcanic soil grow slower and smaller, which makes for a tighter grain, and a very slow, delicate extraction compared to the oak growing in France. American oak, with its more intense approach to its infusion of flavors into the wine will impart vanilla, aromatic sweetness, roasted coffee, coconut, and dill. Compared to French and Hungarian oak, American has a more intense flavor, and a quicker extraction. When it comes to cost, French is at the high end of the spectrum, American at the bottom and Hungarian oak somewhere between the two. If you want the French essence at a fraction of the cost, I recommend Hungarian oak. If you are working with hybrid grapes, experiment with oak cubes and staves of different types of oak to determine the best fit for your goals.

What Size is Right for You

The oak-surface to wine ratio is a major factor to consider when deciding the length of time a wine may age in a barrel.

In a smaller barrels, initially, oak will be imparted into the wine faster than that of a 59-gallon (223-L) barrel, which has just the right surface-to-wine ratio for extended aging without the worry of over-oaking, before the slow controlled oxidation has had its chance to influence the wine in a positive way. In our case, it will take a few rotations of wine in and out of the barrel before we can leave the wine in long enough to make use of the beneficial oxidation process. In other words, the barrel will need a breaking-in period to avoid an undesirable level of oak flavor, which would take years of aging before the wine mellows to a desired taste. American Oak, with its looser grain, is the quickest to impart its oak influence into the wine. Whereas French and Hungarian oak (depending on where the wood was grown and what species), will tend to have a tighter grain that will influence the wine with its oak flavor over a longer period of time. However, wood-to-wine ratio should be your primary consideration over grain tightness. Although the grain may be tighter, the barrel is still of a small size and will oak faster than a larger one. That being said, when preparing for the arrival of a new barrel, you will need to have up to five different batches ready to rotate in and out of it. This is because the first wine may need be racked out in a matter of weeks due to how quickly the wine takes on oak flavoring. After four or five rotations, you can rest easy and allow the wine to age for extended periods without the fear of too much oak character. You can even make a few less expensive wines from kits, juice, or non-premium grapes to go in first so if you accidentally over oak, you will not be doing so to a batch from grapes that you spent a year caring for in your own vineyard or paid a premium for.

With the oak to wine ratio concept in mind, you can determine the correct sized barrel that fits your production output to avoid storing it empty half of the year. If you purchase your grapes annually, simply get enough fruit to keep the barrel full until next harvest (85–100 lbs. for 5 gallons of finished wine/39–45 kg/19 L), and be sure to have extra wine for topping. When growing your own grapes, it may be difficult to project yearly output unless you are documenting and looking back at harvest data from previous years to determine if what you are harvesting will be enough. If you feel it may be a light year, juice pails or additional grapes can be purchased to fill the void. Evaluate your yearly volumes and plan accordingly to keep your barrel full and happy. However, if your wine is in danger of being over-oaked, and you do not have a wine to immediately follow, storing the barrel empty until another wine is ready to go is always an option. Simply rinse the barrel several times, drain, allow to dry, and burn a sulfur stick within barrel and replace the silicone bung. Be sure to check for the presence of sulfur monthly and replace as needed. Another option is to store barrels with a sulfur-citric acid solution, which keeps the barrel swelled and kept form drying out. This method of storage is recommend for well broken-in barrels as the solution will leach out some of the precious oak flavor from a new barrel. Monitoring and caring for your broken-in, but empty, barrel is incredibly important if you plan to continue use of this significant tool in your home winery. Improper storage and lack of intervention can cause contamination of the barrel and spoilage of any wine that eventually goes into it. It is highly recommended to keep wine in the barrel at all times. Otherwise there are options for empty storage if needed.

For an in-depth look at barrel care please read Barrel Care Techniques by: Daniel Pambianchi https://winemakermag.com/technique/84-barrel-care-techniques

In an effort to maintain a fully topped barrel, you will also need extra wine for topping as it evaporates. This evaporation is known as the “Angels Share,” which creates an ullage (head space) in the barrel that needs to be replenished every so often to prevent oxidation and the growth of surface yeasts that could impact the flavor negatively or even ruin the wine permanently. Depending on the humidity of the room, the barrel may require up to 500 mL of wine every two to four weeks to maintain a properly topped-up barrel. Strive to maintain a cellar temperature of 55–60 °F (13–16 °C) and a humidity level of 60–70%. When humidity levels fall below 50% then wine evaporation losses are higher, and levels above 85% are the perfect storm for mold growth. I realize this is home winemaking and conditions are seldom perfect, but do your best to maintain these levels for best results. In the winter when humidity levels are low, use a humidifier that allows the user to set the desired humidity level to keep it consistent. High summer temperatures and humidity levels can be kept in check with an air conditioner and/or dehumidifier.

At cooler temperatures, aging is slowed. At higher temperatures there could be an imbalance in the ratio at which oak compounds are being extracted along with the rate of microbial spoilage becomes accelerated. Be sure to purchase a thermometer and hygrometer so you know what is going on in your barrel storage room at all times. Another thing to consider is for the first two months you will need to monitor the absorption rate of the barrel and top up at least twice a week. As the barrel soaks up a portion of the wine, topping up will be less frequent and can be performed once a month or thereabouts. A good rule of thumb is to have at least 10% more wine than fits in the barrel for topping wine, or you can top up with a similar wine you already have bottled from a previous vintage. Even store bought wine can be used as long potassium sorbate is not an ingredient (as it would cause off flavors with wines that have undergone malolactic fermentation).

Preparing for its Arrival

Before we get our new barrel, we need to have a few things ready. As mentioned above, I recommend up to five batches of wine ready to rotate through the barrel as the first couple wines will obtain oak flavoring rather quickly. The barrel will need a cradle to sit in so it is up off of the floor and not rolling around. There are plenty of pictures on the internet to work from to build your own, or one can be purchased from the barrel seller, often with wheels attached for easy mobility around the winery for racking operations. Or the barrel can sit on a workbench or the floor with four wedges cut from 2” x 4” lumber in the front and back on each side to prevent it from rolling and to keep it elevated a bit off the floor. Typically your barrel will come with a wooden bung. These do not seal well and I urge you to purchase a silicone bung. These achieve an effective seal and are very durable. Be sure the room you are storing the barrel in is close to the recommended temperature and humidity levels outlined earlier.

Working with a Small Barrel

When I was researching the use of small barrels, I was very concerned about an aging schedule. How long will I leave the wine in the barrel? What if I over-oak my wine? Will the wine even be in the barrel long enough to benefit from the slow ingress of oxygen? While all of these are valid questions, one must realize each wine is different and will require a different aging regimen.

When the first and second wine go in, a good guideline to follow is one WineMaker’s Technical Editor Bob Peak's has stated in previous articles: One week per gallon (4 L) rule. This means for a 10-gallon (38-L) barrel, the wine can stay in for approximately 10 weeks. This time frame is definitely not enough time for any sort of oxygenation effects to take place (at first). But as we rotate more batches of wine through the barrel, each batch can kick its shoes off and stay a little longer than the last, as is the case with another schedule guideline that was recommended to me by a couple professional winemakers: The first wine may be in the barrel for just 8 to 10 weeks. The next wine could then stay double the previous time at 16 to 20 weeks and the next 32 to 40 weeks and so on. These time frames should assist you in determining how long to leave each wine in and prepare for how much will be required for topping the barrel off to keep it full at all times. According to Daniel Pambianchi’s “Techniques in Home Winemaking,” the first one or two wines aged in the barrel will be higher in tannin. The proceeding wines will be of higher quality because the wine can age longer as tannins are transferred from the barrel to the wine at a slower rate. Pambianchi goes on to recommend leaving a portion of the first couple barrel-aged batches un-oaked to be blended later to adjust for the right level of oak flavor. This is wise in case the wine unintentionally gets too much oak flavor. The biggest hurdle to jump over is the break-in period, which is all that is needed in order to allow wines an extended stay in a smaller barrel. This goes for 5-gallon (19-L) barrels up to other home winemaking sizes too. Using a smaller barrel is not difficult, it is just different.

Tasting for your Desired Oak Level

When using a new oak barrel for the first few batches of wine, it is important to smell and taste the wine weekly. As mentioned earlier, once a few wines have taken up residence in the barrel, you can taste it when you top-up (every four weeks) to see how the wine is developing and if the level of oak is to your liking. I prefer to slightly over-oak before I remove the wine from the barrel. Once bottled, the oak flavor will integrate into the wine over time and an oak level you were happy with 6 months ago will no longer have the same impact it once did. Over-oaking the wine slightly ensures that some of that oak essence fades to a sweet spot. Just know this determination of oak is completely up to your palate and what you prefer.

Tips

• Once the barrel has gone neutral, meaning the barrel has no oak flavor left to offer, oak cubes can be used. This enables you to use any type of oak while taking advantage of the slow oxidation affects. In addition, the concern of over-oaking is past.

• 5 to 9 gallon (19-23L) barrels may be lifted to an elevated work bench for gravity racking. 10 gallon (38L) barrels and up will require a pump to rack the wine out as it will be far too heavy to lift for gravity racking. Vacuum pumps work well as do diaphragm and impeller pumps. If you have a Buon Vino Mini-Jet or Super-Jet, these too can be used for racking operations. Be sure to have a racking plan before you get your barrel.

• Topping wine can be conveniently kept in a Cornelius keg under the protection of nitrogen or argon. When it is time to top off the barrel, simply fill it with the plastic cobra tap connected to the keg. I recommend oxygen barrier tubing to prevent oxygen ingress affecting the wine, as is the case with vinyl tubing.

• When rinsing or cleaning out your barrel, avoid the use of chlorine in your rinse water by using an in-line carbon water filter. The chlorine can contribute to the production of 2,4, 6-trichloroanisole (TCA, or cork taint) and some molds. You can even use filtered water when mixing sulfite powder and other additives before adding it to the barrel.

• If you are getting serious enough in your winemaking that you are getting a barrel, I highly recommend the purchase of a sulfite testing kit. Whether it be an Aeration Oxidation kit, or the Vinmetrica unit, testing sulfite levels as your wine ages in the barrel gives you a huge advantage and allows you to add the exact amount of sulfite needed to protect the wine from oxidation, rather than guessing and adding too much or too little. These sulfite testing kits provide clear instructions and everything you need to get started. You do not even need a degree in chemistry to perform and interpret the tests results.

At first, I was afraid to get a barrel, most notably the smaller version, especially with all of the horror stories you can read online of folks over-oaking their wines and barrels being a major pain to maintain and take care of. There are even stories of folks oxidizing their wine because they did not monitor sulfite levels or experienced other issues. However, if you monitor the wine’s progress closely and take care of your equipment, after a brief break-in period, small barrels are easy to work with, affordable, and the benefits far outweigh any potential risks associated with aging wine in them. After a while, maintaining and working with small barrels becomes second nature and any anxiety you had fades away.

Further Reading

I urge you to read up on barrel storage, maintenance, and signs of microbial infections to address any potential issues before they get out of hand. Below is recommended reading for barrel care, maintenance and what could go wrong.

-Techniques in Home Winemaking by: Daniel Pambianchi. Chapter 7 Page:189

-Oak Barrel Care Guide By: Tristan Johnson

https://morewinemaking.com/articles/Oak_barrel_care_guide

-Oak Information Paper By: Shea A.J. Comfort

https://morewinemaking.com/web_files/intranet.morebeer.com/files/oakinfopaper09.pdf

Get Crystal Clear About Filtration

This Article Originally Appeared 
in the Dec/Jan 18/19 Issue of 
Winemaker Magazine

Filtration is an important step in the wine’s path from vine to bottle. It is important because stability and clarity are necessary for a product that is safe to bottle, and is attractive to consumers. With the exception of the final sulfite addition, filtration is the final task before the wine will meet the bottling line. As with anything in winemaking, there are different camps that feel strongly one way or another about various topics of the craft- and filtration is no different. Which ever camp you find yourself in, I am here to tell you filtration is easily achieved at home, resulting in a brilliant looking product you will be confident to enter into competitions and proud to enjoy with family and friends. In this article we will explore the how and why of wine filtration along with the equipment needed to do it.

How Filtration Works

First off, we must take a minute to explain what filtration is. Essentially filtration works by passing wine through a filter media, be it a cellulose pad or cartridge. As the wine moves through the filter, any microbes, yeast, or other particles larger than the micron rating of the filter are captured and prevented from moving through the filter media. Producing a crystal clear product, and depending on the micron rating, free of yeast and microbes, in other words: a stable wine.

Why We Filter

Clarity

Let us start off with the biggest reason home wine makers filter-Clarity. Commercial wineries are expected to produce a consistently clear wine, whereas home wine makers are not under such scrutiny. However, even a single pass through a coarse filter-approximately 5-7 microns, will remove the larger suspended particles and give you an edge in competitions and enable you to produce a professional looking product in the comfort of your own home. While fining agents and subsequent rackings will suffice in most instances, there will always be that next level of clarity to achieve by which filtration is the only route. Considering a consumer’s first impression is a wine’s appearance, clarity is a significant factor. Particularly with White and Rose’ wines. The decision to filter Reds is based on artistic / personal preference, or due to necessity (I will clarify on this decision below). Over time Reds will throw sediment anyway, and premium reds are not usually filtered as some oxidation may take place during the process. In some cases the sediment is a sign of quality. Personally, I filter my reds through a coarse filter just to remove the large particles that may be floating around and visible to the naked eye. I I have found this gives me a great looking product and alleviates any fears of floaties in the glass. Later in the article I will discuss which filter size to use when clarification is our main objective.

Microbial Stability

Another reason wine is filtered is for microbial stability. Wines with residual sugar, unfinished malolactic fermentation (MLF) or have suffered the affects of Brettenomyces or other yeasts and bacteria, are at risk for spoilage issues once the wine is in the bottle (although word on the street is if there is Brettenomyces detected in the winery, it is time to burn it down. This is a joke of course). These problems can produce a fizzy, off tasting wine that could even force the bottle to pop its cork or worse, explode. Filtration for microbial stability is seldom performed in the home setting usually due to experience, cost or equipment availability. Coming close to sterile filtration without the big plate and frame or cross-flow filters you see in wineries is possible (I will expand more on this later).

Without the use of filtration, residual sugar can be addressed with the use of potassium sorbate and unfinished malolactic fermentation is kept under control with the use of Lysozyme. However, potassium sorbate cannot be used in a wine that has undergone malolactic fermentation, it will result in a geraniol flavor, which is a flaw. Therefore if you have a wine that has undergone MLF and has residual sugar, getting as close to sterile filtration as possible seems to be your only choice for a stable wine that is safe to bottle.

How Do I Know What Microbes I Want to Filter?

Examples of the microbes wineries are most interested in filtering out via sterile filtration are: Yeasts: Brettanomyces species, Kloeckera apiculata, Saccharomyces species, Zygosaccharomyces bailii. Bacteria: Acetobacter species, Lactobacillus species, Oenococcus oeni, Pediococcus species. Without a microscope and the know-how, it is impossible to get down to the microbiological level of our wine in the home winemaking setting. This makes it difficult to get specific about what we are trying to filter out. Some of these microbes or yeasts can present themselves with off flavors or an offensive nose alerting you to their presence in the wine, which makes them detectable without the use of a specialized equipment or a degree in microbiology. But, in our situation the things we are looking to filter out most are Saccharomyces species (cultured wine yeast) and Oenococcus oeni (malolactic bacteria). This is just in case alcoholic or malolactic fermentation does not finish and we would rather filter than use additives to stabilize our wine (which is not always an option). Yeasts are in the 5-10 micron (µm) range. Bacteria get smaller in size, for example: cocci can be from 0.5-3 µm in diameter, bacilli can range from 0.2-2 µm. As you can see the filter choice does make a difference in what you intend to filter. Although these sizes are simplified, it should prove to be a guide to help you choose the right filter for the job and be used as a springboard for further research. (Let’s Be Clear About Filtration by: Greg Howell (2008)

Filter Pore Sizes

Pore sizes are measured in microns (µm). This means the smaller the number, the tighter the pores in the filter are. Buon Vino pads are rated-the higher the number, the tighter they are (More on this below). The ability of the filter to remove microbes lends itself to the pore sizes which are made to be smaller than the yeast and microbes themselves, not allowing them to pass through the filter media. The usual micron ratings for winemakers are 7, 5, 3, 2, 1, 0.5 and 0.45, along with other sizes for various stages in the process. To further break down the filter types, there are what is called the Nominal and Absolute rating. The nominal rating will filter out most of the microbes above the micron measurement. Whereas the absolute filter rating will filter out everything above the micron rating. The industry standard for sterile filtration is 0.45 µm nominal. Although it is not sterile by microbiological standards (which is 0.2 µm) .45 µm is still the standard for sterile filtration in wine making.

In an effort to assist you finding a good fit for your home winery, below are filter units available to the home winemaker for all yearly volumes produced.

The Mini Jet

This compact unit is made for small scale filtration: 5-10 gallons (20-40L) at a time. This is perfect for those of you working with kits, juice pails and smaller batches of wine. The Mini jet uses a built in self-priming Flo-Jet pump to send the wine through the set of three cellulose filter pads. This pump can also be used to rack wine by bypassing the filter pads.

Super Jet

The super jet is made for medium scale filtration: 13-26 gallons (50-100L) at a time. This unit uses 20×20 cm cellulose filters pads to do the job, and come in the same rating as its Mini Jet counterpart. The Super Jet has also has a Flojet pump, and like the Mini, can be used for racking wine. This gives you more bang for your buck and allows you to pump large volumes of wine between tanks and other large vessels. The Super Jet is equipped with a pressure gauge so you know when the pads have become clogged with debris and need to be changed.

If you are making higher volumes of wine and have deeper pockets, the Super Jet also has a six-pad option for filtration of up to 60 gallons at a time. The extra 3 pads allow for a longer filtration session without the hassle of replacing pads. It can also be used for racking wine from one vessel to another, which is great as another piece of equipment is not needed for wine transfer.

The filter pads for the Mini and Super Jet come in three different grades.

• Coarse Number 1 is approximately 7 microns and is meant for filtration of wines that are clear, but have some large suspended particulate. Perfect for reds and preparing a wine for filtration with tighter pads.

• Polish Number 2 is approximately 2 microns and is meant for filtration of white, rose, or if you want to further polish a red wine. This set of pads should be used prior to using the number 3 pads.

• Sterile Number 3 is approximately .5 microns. Although this pad set is labeled "sterile", it does not meet the industry standard of sterile filtration, which is .45 nominal. This pad set may remove some yeast, but should not be used in place of potassium sorbate when there is residual sugar present, or in place of Lysozyme if malolactic fermentation failed to finish. When using this pad, be sure to first filter with at least the number two pad set first, as any particulate in the wine will quickly clog up a pad of this micron rating. This pad set would be used if the polish pads did not filter to your liking and you desire a wine higher degree of clarity.

For very small volumes, there is a plate and frame filter on various wine making websites. This filter can be used by gravity or the wine pushed through the filter between kegs with inert gas. However, according to Techniques in Home Winemaking By: Daniel Pambianchi (1999) page 177, the gravity versions may introduce excess oxygen into the wine due to the length of time it takes to perform the filtration process. Feel free to research these filters on your own.

Inline filters and Vacuum Pumps

The use of inline filters is becoming more popular as vacuum pumps like the Enolmatic, the All in In One Wine Pump, and home made vacuum pump set-ups are being used by home winemakers for various duties around the home winery. A major benefit to using inline filters is oxygen ingress is greatly reduced thanks to the whole filter operation being enclosed. An added bonus is the filter housing is easier to clean and sanitize too. Below are inline filtration kits for home winemakers.

The All In One Wine Pump

Among the many uses for the All In One Wine Pump, one is filtration. This unit uses an inline 10" filter housing, with cartridge filters available in many different micron ratings. The owner and creator of the All in One Wine Pump, Steve Helsper provides a detailed list of equipment and some helpful set up tips at allinonewinepump.com. This equipment can be purchased from filtersfast.com. It is recommended to filter and bottle in separate sessions, as a steady flow is warranted for effective filtration.

Note: The equipment list should be closely followed as the incorrect filter housing could be purchased if you are not careful. If you choose to buy the items on the list else ware, be sure to purchase the filter housing without the red button relief valve, as this valve may open during the vacuum operation preventing a good seal. The housing with the red button can be used with inert gas between kegs, and wine pumps.

The filter cartridges, such as a .45 nominal sterile cartridges by BevBrite can be purchased from Morewine, as these cartridges are said to work with any 10" housing. BevBrite cartridges also come in 5, 3 and 1 micron ratings. When reading up on BevBrite or other cartridges, you may see they have an efficiency rating. This simply means what percent of material will be filtered out at that particular micron rating.

As an example, below is each level of efficiency and what they mean for their 3 micron filter:

• High Efficiency: Removes 90% of the material 3 micron or larger in a single pass.
• Super High Efficiency: Removes 98% of the material 3 micron or larger in a single pass.
• Absolute Efficiency: Removes 99.8% of the material 3 micron or larger in a single pass.

(Efficiency ratings from Morewine!)

The Enolmatic

The Enolmatic has its own filter housing and filter cartridges made specifically for the unit. Filter sizes come in 5, 1 and .5 microns, which can be cleaned with Powder Brewery Wash after filtration to be used again. The filter housing is installed between the vessel of wine and the Enolmatic, and filtration takes place as the wine is bottled. This makes for one less step in handling the wine, which reduces exposure to oxygen and other baddies.

Vacuum Pump Build

For those of you that have built their own vacuum pump set-ups for racking and degassing wine, the list of filtration equipment for the All in One Wine Pump can be used. The difference is that the All in One Wine Pump has a precision valve that regulates flow control of the wine. This comes in handy to prevent wine flowing through the filter too fast. To remedy this, you can install a thumb valve in between the vacuum pump and over-flow container. This allows some air into the line to reduce the flow-rate, of which does not come in contact with the wine. For more information on building your own vacuum pump racking kit and installing an inline thumb valve, please see my article Moving Wine and Using Pumps in the Apr/May 2017 issue of Winemaker Magazine.

Tips for a Successful Filtration

1. When using a plate and frame filter, be sure to run a sulfite citric acid solution through the pads. Doing this not only sanitizes them, but it will also remove paper particles and other debris. One tablespoon of each per gallon will do. In my home winery, I run 5 gallons of this water through each set of pads. When I start the filtration procedure, I divert the first bit of liquid coming out of the filter into a pitcher, as it will be mostly water at first.
2. Filtration has its limitations and it can only do so much for the longevity of a wine’s clarity if certain tasks are not carried out during the wine making process; most notably cold stabilization and protein stability. If a wine is not cold stabilized by exposing it to below freezing temperatures for a period of time (usually 2-6 weeks depending on the temperature the wine is exposed to), the wine will throw tartrate crystals which will settle to the bottom of the bottle when chilled. While these crystals are not harmful, they can by mistaken for glass and they certainly are crunchy! White wines should also be protein stabilized by using Bentonite. This will prevent a haze from form forming and swirling around the bottle when you pull it off the wine rack. No amount of filtration will prevent these two things from happening and need to be completed during the winemaking process.
3. Be sure to filter at the Correct Stage in the process: Wineries are equipped to filter wine at various stages in the process, no matter the clarity or murkiness of the wine. Whereas we homers should stick to filtration at the end of the process when the wine is clear. You may be asking yourself: why would I filter a wine that is already clear? Filtration should take place after the wine has had ample time to for the suspended particles to settle to the bottom of the vessel. This takes time, racking from one vessel to another and possibly the use of a fining agent. Exceptions to the this recommendation are wines that fall bright faster than wines made with fruit such as kits and juice pails which lack the fruit matter from grapes. The fruit matter creates sediment that would quickly clog up the filter pads if filtered too soon. To get back to the question you had asked yourself above: If wine is not clear, as in read a newspaper through it clear, the filter pads or cartridge would immediately become clogged preventing the wine from being filtered. But if I can read a newspaper through it, why would I filter? As mentioned above, there is another level of clarity to be achieved by filtration. Large particles floating in the carboy may not be visible until the wine goes into the glass, and by then it is too later to filter! The difference is clear in a comparison between filtered and unfiltered wine, especially when you are outside and the sun is shining through your white or rose; the word brilliant comes to mind. When making the decision about the best time to filter, remember these six words: Filter no wine before it’s time.
4. Be sure to follow the instructions for which ever filter you use. For example, when using a plate and frame filter like the Mini-jet, be sure to insert the pads with coarse side facing outward toward the black knobs. Also, be sure to use the same grade of pads, you cannot mix filter pads of different micron ratings.
5. Prior to filtration, be sure to rack the clean wine off of any sediment as not to clog the filter. Buon Vino sells a pre-filter to install between the wine to be filtered and the filter itself. This protects the pump from oak bits and fruit matter to ensure it has a long life.
6. This should go without saying, but be sure to sanitize everything that will touch the wine, with the exception of a new filter cartridge which should be ready to use out of the bag.
7. Ensure your sulfite levels are in line before filtration. Plate and frame filtration can promote oxidation and sulfite is needed to protect the wine. If you have no method of sulfite management, give it a dose prior to filtering your wine.
8. If you intend to filter with a very tight pad such as a .5 or even a .45 micron filter media, it is necessary to step-filter down to that particular rating. For example, filtration through a 5 micron pad, then a 1 micron, and then down to .8 or .5 then .45 is recommended. It is impossible to go straight to the tighter pads immediately no matter then clarity of the wine. Reds have an even more difficult time moving through the tighter pads in general due to the amount of suspended particles (compared to White and Rose’ wine). So Reds should only ever need a polish filter unless further action is required to achieve microbial stability. At that point step-filtration is absolutely necessary.

In Conclusion

As you can see filtration is a huge subject with a lot of ins and outs, most are out of the scope of this article. I feel in this article we just scratched the surface and this topic will require further research on your part. But rest assured no matter what volume of wine you make, there is a wine filter for you. Forget the rumors and hearsay you have heard about what filtration can do to your wine, ask yourself what it can do for your wine. And rest easy knowing that there is no wine filter available to us homers that can strip color or flavor. So grab yourself a filter, and get ready to shine!

Let’s Be Clear About Filtration by: Greg Howell (2008) Australian and New Zealand Grape Grower and Winemaker Issue 538 page 108-112

Techniques in Home Winemaking by: Daniel Pambianchi (1999)