Winemakers have long been using oak barrels for winemaking, but in recent decades oak alternatives become widely used with some advantages and disadvantages. The choice between oak barrels and oak alternatives depends on the winemaker and the situation. You might want to consider oak barrels, oak alternatives, or some combination of the two. Below you will find some guidance to help with your choice.
We now have much more convenient means of storing large volumes of wine, yet wineries and winemakers continue to use oak barrels for there reds... why? Part of the answer is consumer appeal. People like to see stacks of barrels and it does give a winery some level of street cred. The main reason that oak barrels are used though is that they offer some benefits that are very difficult to replicate with oak alternatives and stainless tanks.
Wine barrels breathe and allow a minuscule amount of oxygen into wine. In small doses, oxygen stabilizes pigments directly after primary fermentation. As more time passes, oxygen encourages the polymerization of short chain tannins into long chain tannins. These long chain tannins contribute to a silky mouth feel, whereas short chain tannins are harsh and unforgiving. It is very difficult to replicate the micro-oxidation that occurs in a barrel with out the use of very expensive MOx equipment. Even with this equipment, it is easy to introduce oxygen too quickly and ruin the wine.
Even old wine barrels that are not so oaky anymore will offer the benefit of micro-oxidation and can be quite useful if maintained properly.
Because a barrel is slightly porous, some wine will be lost to evaporation as it seeps into the pores of the wood and floats off into the air. Winemakers generally need to top up the barrel with wine every two to three weeks because of this phenomenon. To keep a 59 gallon barrel topped up through the year, you may need to set aside an additional 6 or 7 gallons of wine. This hardly sounds like a benefit of a barrel, but it is. This slow evaporation of wine concentrates the flavor compounds, tannin structure, and aromas of the final wine.
It is very difficult to replicate the effect without very expensive equipment or unconventional procedures. Large wineries can use reverse osmosis to achieve a similar result. At home you can remove some juice before primary fermentation to improve the skin to juice ratio (and make a rosé from that juice...). You can also achieve some level of concentration by chilling the finished wine until ice crystals form and racking the wine off the ice.
This is the obvious benefit of oak. Oak can add flavors like vanilla, spice, coconut, chocolate and nut and more. The type of oak and the level of toast on the barrel can significantly effect the oak character imposed on the wine. A heavy toasted american oak will add a smoke and spice to the wine where a medium toasted french might add more vanilla. The process used to make the oak staves can also effect the flavor. American oak staves are generally sawed, while french oak is generally split.
Downsides of Oak Barrels
A major downside to oak barrels is that they are expensive. A new 59 gallon oak barrel costs anywhere from $500 to $2000 and releases most of its oak in the first two years. Another inconvenience is the maintenance involved in a barrel. To store a barrel without wine, sulfur wicks need to be burned inside periodically or the barrel needs to be gassed with sulfur to reduce the risk of microbial contamination or mold growth. To avoid this, most winemakers will not empty one wine from a barrel until another wine is ready to replace it. This is more challenging with the small size barrels (<30gal) as they impart oak dramatically faster and often the wine will need to be removed well before the next harvest.
For the home winemaker, a great way to dabble in oak is to use oak alternatives. Oak alternatives include barrel staves, oak chips, oak cubes, spirals, etc. Oak alternatives can provide all the benefits of regular oak barrels with the exception of micro-oxidation and concentration. Oak alternatives offer several unique benefits over oak barrels
Arguably the biggest advantage to oak alternatives is the price. A 1lb bag of toasted oak chips can usually be found for less than $10 and is enough oak to treat 10-30 gallons of wine, depending on the level of oak that you are looking to achieve.
With oak alternatives, many levels of toast or even different species of oak can be added to perfectly dial in the finished wine. All of the toast levels available for barrels are available for oak alternatives, including; light, medium, medium plus, medium long, and heavy toast. An advanced winemaker may choose to stagger the oak addition and add lighter toasts with harsh yet protective tannins during fermentation and progressively heavier toasts with softer tannins as the wine is aging. You may also consider some combination of french and american oak to achieve more complexity.
Oak alternatives have a high surface area to volume ratio, causing them to very quickly release oak into the wine. The smaller chips release most of their oak in the first two weeks of use. This allows the winemaker to gradually add oak and quickly see results to decide of more oak is necessary. Be careful when adding oak alternatives though, because within a couple weeks you can go from no oak to over oaked. Taste frequently when using oak chips to minimize the risk of over oaking.
One large oak tree can only produce between one and three full size oak barrels but can produce several tons of oak alternatives. American oak barrels are in
extremely high demand with the recent boom in small distilleries causing some concern for a shortage. Rather than discarding of old, yet healthy wine barrels one can continue to use them for their micro-oxidation effects and concentration effects but supplement with oak alternatives. This is more sustainable and should not cause any reduction in final wine quality if done properly.
Oak barrels are great but they are a large investment. If you are just getting started in winemaking, consider using oak alternatives for a couple years. You may be very happy with the results using alternatives and great wines can be made without the use of barrels. Once you have built some confidence with your wine
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