By: Thomas J. Payette, Winemaking Consultant
Next to sound ripe fruit, great winemaking control during the harvest and excellent blending – finings trials are a next great resource to possibly “fine tune” your successful hard work. This task is often overlooked or under performed due to time and the skill limits of the winemaker. Fining agents must be used as a delicate tool to refine a wine or juice and one should not seek to make a flawed wine desirably drinkable with the wave of a “magic fining wand”.
Before attempting to refine a wine with fining agents make sure the wine is aromatically sound and at optimum by doing a quick copper sulfate aroma trial. This may be the simple action needed to bring in the aromatics desired and reduce or negate the need for a fining. Always perform the fining trials and use a large spectrum of fining agents since not all wines and fining agents work/react as predicted. We, as winemakers, are often surprised at unexpected findings.
The most difficult portion of fining trials is to have an understanding of working with the limited and small volumes of juices or wines and how to apply the small scale lab trials to the larger tank volumes. Once one has a clear understanding and methodology the tasks become easier. It may take several fining trials under ones belt before it becomes second nature and the task becomes “a piece of cake.”
Equipment Needed for Fining Trials
Most winery labs have the basics and one should be able to acquire additional items needed with little financial outlay. Here is a list of basics.
1. 375 milliliter screw cap wine bottles (splits) – may reuse these.
2. Accurate scales
3. 500 ml beakers
4. 500 ml Erlenmeyer flasks
5. Stir plate with magnetic stir bars
6. Distilled water or winery tap water used for mixing fining agents.
7. Graduated cylinders: 50 mil, 100 mil, 250 mil
8. Pipettes: 1 and 10 milliliter serological pipettes
9. Wine glasses – never forget the wine glass!
Some Common Fining Agents
and Their Projected Uses
Casein: This is the principal protein found in milk and milk is approved by the TTB ( Tax and Trade Bureau) to be added to wine. Casein is positively charged and is used mostly as a fining agent in whites wines that have been in the cellar for an extended time – perhaps over two years. The action of casein tends to clean up some color issues as well as remove some of the aged qualities including off contributing color compounds. Each wine reacts differently to casein so trials must be performed in the lab, on a small scale, to understand how your particular wine will react. Either follow the suppliers recommended rates or if using milk you may use up to 7.5 liters of whole or skim milk per 1000 gallons since that is the TTB limit.
Egg Whites: (Albumin): A very proven effective and soft approach used for a very gentle fining mostly on red wines in barrel. Only the whites of the egg are used, mixed with a “pinch” of potassium chloride salt and a small amount of water. Stir the egg white mix gently into the barrel and allow the wine to settle for 30-45 days. For larger wineries that want to do a trial in the cellar one could use: One egg white in one barrel, two egg whites in another, three in another and so on up to a typical maximum of 6 egg whites per barrel. Make sure to do this on the same wine in barrels, of nearly the same age, for a good comparison tasting. This would be an excellent way to do a cellar trial in the winery with very controlled results if you find fining trials difficult in the lab. Dilution schemes of egg whites in the lab are difficult but do the best you can.
Gelatin: Gelatin is a great fining agent typically used early on in the juice or wine. It is known for being aggressive and potentially “stripping” the wine is more likely with gelatin. That said suppliers have rapidly introduced what I call “target specific gelatins” that can enhance or mute certain aromas, and modify specific areas of the palate. These are much more refined products than say 20 years ago when “bloom and mesh” was the only real differentiation between different grades of Gelatin. Gelatin is made from collagen in animals and typically binds with larger molecular weight [tannins / catechins etc] and removing more phenolic compounds from the wine. So if a wine is heavy in tannins and phenolics a review of a gelatin fining trial may be in order. Gelatin does absorb and remove color so use with caution. As always – do trials in the lab first. Because different products have different recommended rates I am steering clear of making any blanket recommended ranges to try and will refer you to the supplier of the specific product you care to experiment with.
Isinglass: An amazing agent because it is fish collagen or sturgeon bladders ( buoyancy bladder ) I am told. Who in the world thought of adding this to wine? This is a gentle protein fining agent used mainly on white wines to help elevate / improve the aromatics and improve clarity with improved lees compaction if used with bentonite. Most likely used 30-60 days prior to bottling and while “finishing the wine out”. A very gentle fining agent and worth trying in the ranges of 1/16 – 1/3 pound per 1000 gallons. A very nice, soft fining agent and even try it with red wines – you may be surprised at the results in your trial and decide to use it on your reds. Some colleagues in the Napa Valley have seen great results with Isinglass on their reds.
PVP: (Polyvinylpolypyrolidone) This is a synthetic material that binds mostly to athocyanins (color) and catechins (smaller phenolic compounds). Often used to remove browning in wines and pre-cursers to browning or brighten up a pink wine. This agent also helps remove bitterness in some wines. Most often used on wines but some also fine juices with PVPP especially on compromised or moldy grapes. Range of use is between 0.5 and 5 pounds per 1000 gallons and wines must be filtered prior to bottling.
Bentonite: This is a widely used fining agent to achieve protein or heat stability in white, blush and light Rose wines. Bentonite is a clay mined in areas of the world that contain high quality pockets of these materials. Some bentonite is sodium based and other are calcium based bentonites. Calcium bentonite is used often in sparkling wines as a riddling aid but most wineries use the sodium based bentonites in there typical winemaking regimes. Trials with bentonite may be used to determine the amount needed to achieve heat stability. Using bentonite up to 5 pounds per 1000 gallons shows minimal stripping and some varietals of wine may need upwards of 10.0 pound per 1000 gallons. Conversely some wines may not need any bentonite although some winemakers see improved attributes to their wines with a small 1.0 pound per 1000 gallons even if no bentonite is needed for heat stability. Heat stability is very important for your wines so consumers are not turned off by your label if your wine should throw a protein haze. Give serious consideration and test all of your white and light red wines for heat stability.
Sparkloid: This agent “fell out of fashion” about two decades ago but it is back strong. Try trials with this agent to get that extra sparkle in the clarity for your wine. Technically a Polysaccharide and it is extracted from the cell wall of brown algae. This agent is soft on color removal but enhances clarity and filtration. Most winemakers use this agent in the 0.5 to 4 pounds per 1000 gallons and staying in the lower ranges.
The above are not by any means the only fining agents used in the wine business but they are perhaps the most commonly used. Many winemakers are starting to move away from fining agents, agents that remove things, to adding agents and building their wines. With better fruit maturity winemakers report not needing to “remove to improve” but dialing in with items such as pictured here. This is an ever expansive group of items with new items being added quickly. Keeping in mind they are new we don’t know all of the long term ramifications of their use.
Bottom line whether looking to fine or add – trials in the laboratory are essential and waiting to taste and test those trials can be beneficial so the wine and agents can “marry” and then allow the wine glass to show better what the results are and will be.
Other Helpful Tips with Fning Agents
Make sure the wines or juices are low in Carbon Dioxide gas since the bubbles may attach to the fining agents preventing them from settling in the tank or lab beaker.
All fining agents should be fresh and free of off or undesirable aromas and flavors. Use cellar batches so results match.
PH affects the rate of settling – lower pH wines settle faster in almost all cases of fining.
The ultimate goal of a fining trial is to use the least amount of fining agent possible to achieve a desired improvement to a wine or a desired stability, such as protein and heat stability, needed prior to bottling.
After reading this article, if your winery does not currently seek improved wines through fining trials, sit down for about one hour and start to develop a plan with a calculator. Think of how you can perform fining trials in your lab and set aside future time to work with your plan. You will be amazed at how much refining can be done to wine and how easy it really is. Make this a part of your work improvement program this year! Give it a shot!
If you would like more information, please contact me (Tom Payette) at 540-672-0387.