By Thomas J. Payette, Winemaking Consultant
Continued from Part 1 which ran in the
January – February 2018 issue of
The Grapevine Magazine.
Monthly Management
Whether full or empty, each barrel needs monthly attention. Try to store full and empty barrels at or as near 50 degrees F when possible.
When full: One will need to taste and check the free Sulfur Dioxide and pHs of these wines monthly at a minimum. After this check, additions can be made to the wines in the barrel and then they can be topped. Topping is one of the keys to keeping a barrel safe from bacteria spoilage. The wines must be of sound chemistry to make this a successful statement and the topping wines need to be “clean”. The author will often use wine from a tank that has been filtered and nearing bottling to know the bacteria load is greatly reduced from that vessel.
When empty: Once again we will need to visit each barrel monthly. In all cases the barrel will have been rinsed and sulfured prior. We should return to these same barrels and, retreat with Sulfur Dioxide by gas or wick (see above) to insure the barrels integrity will continue to be sound.
Where
Most work with empty barrels will happen outside on a crush pad or strung out in caves and warehouses. When possible, try to have as much space and ventilated air moving through the workspace if using liquid Sulfur dioxide or wicks/discs. When possible, the author prefers to unstack the barrels, remove the bungs, look inside the barrel with a flashlight and then smell the barrels at each visit.
If the barrels must stay in place, one can easily work with them also but some of the more critical reviews of sight and smell become more cumbersome.
Rain
At certain times, at certain winery locations, the author likes to use Mother Nature. It is not uncommon to plan a day’s barrel work around the weather. If the weather forecast is for rain the author finds advantages, with uncovered crush pad areas, to do a days barrel work, rinse the interior and then allow the barrels to remain on racks, bung down, in the rain to get a nice soaking cleaning on the exterior as well. This can also apply in conjunction to the swelling procedure above but with barrels full of water and bung upward. Please try this experimentally first on a small batch of barrels since some wood discoloration may take place and not be visually to ones liking.
Always clean the bung opening area and when needed one can cauterize / burn that area again. This process may be needed about every 5 years or so at the maximum and a special tool is needed for this process.
Tartrate Removal
Tartrate removal can be a nuisance for those that focus on it. In general it should not be a huge issue. Do note some winemakers care to cold stabilize their wines before placing in barrel for this reason. Most do not however. Also note that when one looks inside the barrel one will see more tartrates because they typically “fall out” and go to the bottom. In the case of sur lie wines in the barrel the yeast layer does a great job of protecting the bottom of the barrel from tartrate adhesion to the wood.
A high-pressure rinse may remove these tartrates effectively. A hot water rinse my help them “flake off” and dissolve more readily.
Some winemakers use a high pH (warm water helps here) soak followed by a light citric acid soak. This can be very effective in tartrate removal. Makes sure the soda ash, the high pH solute, and citric acid, the low pH solute, dissolve completely before adding any one of them barrel.
Some more European trained winemakers will insert a stainless steel chain and have the less stipend “summer help” roll the barrels with the chain inside to knock the tartrates free – then rinse and Sulfur. Be sure to devise a way to retrieve the chain from the barrel.
In most cases, however, the tartrate removal is not a huge focus for the majority of the winemakers due to practical applications.
Tools Needed
Many tools for barrel care may be purchased at winery supply stores, cooperage houses and other specialty suppliers specific to these type products. Research your needs and then contact these companies to see what they offer. In general, only a good barrel rinser, good to great water pressure (chlorine free) is needed and way to introduce the SO2 – wick or gas.
Glass head barrels: A great tool to be able to see inside the barrel when performing certain tasks from burning sulfur wicks, filling, rinsing, lees stirring etc. Watching fermentation and malo-lactic with these glass head barrels can be fascinating beyond the other features. Every cellar should have just one of these glass head barrels to better know what is happening inside their barrels with certain specific functions.
Humidity
Humidity is undoubtedly a factor when dealing with barrels. The author prefers a less humid cellar to make sure the vacuum needed inside the barrel is fully established on barrels with wine in them. If barrels are kept full and production practices to store few barrels empty for any length of time are employed, this can be the best way to use barrels to their fullest and best capacity. There is some “angel’s breath” evaporation loss but that is a part of the process. If a barrel is stored for less than three months empty most will have few to no issues with reswelling.
Spicing It Up!
Some winemakers prefer to cold stabilize their wines before placing them in barrels to prevent tartrate build up in the barrels. (Referenced above) This can be effective but most winemakers do not do this in large practice.
Burning a sulfur wick in a barrel (5-6 grams) does two things. It puts sulfur dioxide in the barrel as well as displaces oxygen with carbon dioxide. This practice may lend toward mimicking by the winemaker using a carbon dioxide flush on their barrels then using pure liquid sulfur dioxide, following. Many large wineries use liquid Sulfur Dioxide and this may apply to their needs best. Many large wineries also could make dry ice, on site, and this could be used as the Carbon Dioxide source. This may be the way of the future to help combat spoilage bacteria growth in barrels. This may well be the future established standard for proper barrel care.
Wrapping It Up
Tackling the barrel care issue is a trying one but actually an easy one. There is only one way to do it right. The way it works for your cellar. There are many off branches and combinations of what has been described above. Please take from this article anything you think may help your current process and refine, for the better, what will work best for your winery and wines. As can be seen these are some must do processes but most recommendations have some variation.
In all be diligent and respectful of the barrels in your cellar and they will provide many years of service to you, your cellar and your wines.
Other Helpful Tips
Alcohol is less dense than water or juice. It is not all too uncommon to fill a barrel with water to validate the barrel will not leak, only to find a barrel may develop a leak later on. These leaks can typically be fixed on sight of the winery with little effort.
Do not fill a barrel with wine you know to be bacterially unsound. This will only start the spread, further, of the unwanted bacteria.
Smelling the barrel is one of the best ways to acknowledge its condition and readiness to potentially help or harm your wines in the cellar.
Whether full or empty, each barrel normally requires some form of monthly maintenance.
Topping, on time, is critical and resulfuring, on time, is critical.
Lower storage temperatures (50 degrees F) can be a very useful tool and one more winemakers should try to strive to use.
Resist the temptation to store barrels outside. There are many wood boring insects that may take fancy to this easy target leaving the winemaker with leaky barrels. Small periods of time outside may be acceptable.
American oaks tend to need reswelling more than European woods. The author has noticed American oak may develop more ethyl acetate type aromas when stored empty due to a reaction of the wood, moisture and Sulfur dioxide. This is generally not a bacterially generated ethyl acetate aroma if sound procedures are followed and not a concern – just an observation winemakers may notice in their cellars and to be aware.
Uprights and ovals beyond the 600-liter capacity are beyond the scope of this article and care should be taken to establish contact with appropriate sources to secure proper methods of working with these wood vessels.
References:
Verbal discussion with Jacques Boissenot, Chris Johnson, Joachim Hollerith and Jacques Recht.
Many thanks to Mark Heinemann and all the Demptos Cooperage team for their help.
Short Course:
• Visit each barrel monthly.
• Use the basics of this article to establish your best procedure.
• Make this a part of your HACCP plan.
• Be timely and don’t ignore your barrels. Respect them.
• Cool temperatures aid you with full or empty barrels.