Oak Chips, Sticks, etc. Info
Oak is a truly remarkable wood - and that isn't the carpenter in me speaking although it’s pretty good for that too. Oak’s gentle influence in alcohol from spirits to wine to beer that makes it desirable. While oak barrels are well known for their use in wine-making, distilling, and beer brewing, the plucky homebrewer doesn’t need to have giant barrels scattered around the yard to enjoy oak’s wonderful nature. Utilizing oak chips, cubes, spirals, staves or chunks is a great way of adding character that can elevate your usual respectable home brew to a particularly well-rounded beer. There is some risk though - too much ‘oaking’, as it is known, can make your drink taste more like you’re gnawing on a stump than drinking a fine ale. And how do you ensure your chips are sufficiently clean that you aren’t introducing bugs into your brew? Steam, or boil them? Soak them in a single-malt?
Oak is traditional, functional and plentiful. When used in barrels, it is water tight, yet slightly porous to air. Oak contains relatively high levels of tannins, but not as high as other hardwoods, such as chestnut. Apple and cherry wood can be used for taste but introduce an off-putting smell. The right amount of tannins, as can be found in oak, adds tasty bitterness and mouthfeel. Too much can be like a tea when the teabag has been left in too long. Oak isn’t necessarily the best in every situation, but in terms of availability and consistent quality, it’s a winner. Oak chips are an effective way of modifying and adding flavor to your beer or wine - and chips are far cheaper and easier to manage than buying new or used oak barrels that hold up to 50 gallons. Generally comparing beer that has been oaked to one that hasn’t will show subtle variation - the oaked beer will generally be cleaner and smoother in backbone and aftertaste, with the possibility of vanilla notes if the oak has been toasted, depending to what degree.
Common Types of Oak The three common oaks are American, French, and Hungarian. Oak from individual trees or areas can vary hugely between trees right next to each other and trees many miles apart, meaning a rule of thumb doesn’t always apply. In addition, many marketers work hard on their product pushing lines around tight grains, traditions, when scientifically, oak differs just based on which parcel of land it was grown on. That means taste-testing is important! Generally speaking though, American is stronger in oak flavor and produces more vanilla notes. French oak is more subtle on the oak flavor, can be ‘sweeter’, and has more tannins. Hungarian oak offers mellow smooth vanilla notes. It's a bit harder to aquire, but provides very desirable flavor profiles. Oak can add vanilla flavors, depending on the toast level. Toast refers to the traditional firing of the inside of an oak barrel during the manufacturing process. Toasting of the oak creates melanoidins, as heat breaks down carbohydrates into sugars. Heavier toasts create charring and more ‘confectionary’ compounds, with caramel and butterscotch flavors expected.
Oak Chips are added to the secondary fermenter, where the cooler, understated flavors are able to come through without bubbling off during the primary ferment. Chips can also be soaked in bourbon or whisky prior to adding to add more complex and distinct flavors as well. Big brewers are known to age their beers in used barrels - many stouts have been aged in used bourbon oak barrels to add depth, while sherry and port barrels are used for lagers to add unique aromas and tastes. Chips can come toasted, or untoasted. Untoasted wood may be fired by the homebrewer himself, with oak prepared in a similar way to how wood for smoking meats is prepared - the wood is soaked beforehand and not burned but heated slowly when toasting. (Of course, oak used in brewing can be used for smoking later too!) The exact nature of the oak depends on the type, quantity, and time left in the secondary - which makes for plenty of experimenting and tasting. Surface area plays a role here. Oak chips are only second to oak dust in terms of surface area (the amount of oak touching your beer directly). Things like cubes, staves, and spirals have lower surface areas and take longer to release wood flavors. Too little oak won’t impart enough flavor, and overcompensating by leaving a small amount of oak in for longer adds excessive tannins. On the other hand, too much oak doesn’t allow for complex flavors to emerge before an overwhelming wood flavor takes over. It’s highly recommended as your wood ages in the secondary to understand how the oak flavor is being added - either strongly, or more mellow, and how long it takes to taste just right. Typically half an ounce will be plenty for use in a 5 gallon imperial stout. Tips: Remember, chips float! It’s far from useful to have half of your wood not exposed to your brew, so most brewers place chips into a clean sterile hop bag and weigh the bag down with something heavy and inert. Surface area: The more surface area an oak chip has the faster it will work. Most reference material suggests chips act faster on beer than oak cubes simply due to the amount of exposed wood able to act on the liquid. Fitting a bag full of chips inside a secondary might not necessarily be easy depending on what you use for a secondary vessel (if you use one). Most carboys are narrow necked and may make it hard to get the chips in and out. Plan for this in advance. Oak flavors can dissipate over time in the bottle - if you’ve let your chips in too long, more settling time should help alleviate any overly strong tones.
Sanitizing of Oak Chips All brewers fear introducing anything into their brew, but reference material varies heavily on this subject. Here’s a summary of different approaches for adding oak chips to beer: No sanitary steps for wood in a package - just throw the oak chips in. Add chips to water and steam via microwave to remove bugs, introduce water only. Boil just enough water to cover, place chips in boiler, cool, place wood and water into secondary Soak the chips in vodka, bourbon, or rum for at least a day, and add it all to the beer. Not always an option on a budget! Pressure cook wood chips for 20 minutes. Pasteurize the wood at 195F for five minutes. Sanitize wood with chemicals such as campden tablet solution. (Not highly recommended as this can damage the wood and flavor the beer - but is a method utilized by some)