I just finished up a new post for HomeBrewStuff.com all about getting your wort cold and keeping fermenters cool. I thought up this topic while preparing to move my Russian River Consecration clone from primary to secondary. Why did I think this a great topic to write on? Because we hit near record temps, 108F. Man that was a hot day!
Back on the Consecration Clone, the kits come with oak chunks from the actual barrels that Vinny, from Russian River, uses. I've used wood in my beers many times and thought I'd share a little of research, knowledge, and experience I've gained.
First thing you need to know is that not all oak is the same. The three most common oak varieties are American, French and Hungarian. American oak is sweetly aromatic lending a vanilla aroma and flavor, French oak is is also sweetly aromatic and tends to provide a full bodied mouthfeel. Hungarian oak tends to provide a large vanilla profile and while I have never used Hungarian oak it’s noted as possibly lending notes of dark coffee and dark chocolate.
The second aspect of oak is toast level. Typically there are three levels of toast: light, medium, and heavy. The heavier the toast level the less oak flavors and aroma and more of the uniqueness of the varietal. On the light end is cinnamon and vanilla; on the darker end are raisin, coffee, dark chocolate, and "spice"
Oak comes in several forms for home brewers, chips and cubes are the two most common. Chips are small and thin allowing for faster transfer of flavor, about 1 to 2 weeks for full flavor extraction. Cubes can take a few months. The third option, barrels, is quickly becoming a big deal in the beer world. Both pro-brewers and home brewers are using barrels to make truly amazing beers.
One reason brewers are using barrels is that the wood is slightly oxygen permeable. Over time, a small about of air gets in. This is useful for a number of reasons. For example, sour beers are made with yeast and bacteria that benefit from a little bit of oxygen over the course of time. In place of a barrel, a home brewer can use plastic buckets and oak chips. Plastic buckets are more oxygen permeable than barrels so you can't age as long as you can in a barrel.
Another benefit of oak, be it chip, cube, or barrel, is that the sour beer yeast and bacteria can live in the wood. Many brewers infect their barrels once the oak flavor is diminished and use these bugs batch after batch without needing to add anything extra.
So it’s time to add some oak to a beer! First you need to decide if this is going to be for oak flavor, an oak/spirit flavor, or for souring reasons. If you intend to just get oak flavor you can add chips or cubes directly to the fermenter after primary fermentation has slowed down. Stores typically sell oak chips in 2 ounce bags. This is more than enough for a standard 5 gallon recipe. I usually use only one ounce for subtle flavors or two ounces for big and bold oak presence.
Most stores will tell you there is no need to sanitize the oak prior to adding and this is likely true.....but I almost always sanitize my oak first, which is where the spirits come in. Soak the chips in either water or something like bourbon, whiskey, even red or white wine, just enough to cover the chips without floating too much. Alcohol will kill most bad bugs. If using water, I microwave for one minute using a microwave safe bowl and water just covering the oak chips. If using spirits, I usually dump it all into the fermenter, chips, spirit and all, with water its just the chips. If you use a spirit to sanitize it will most likely carry over some flavor into the finished beer. This is a great way to experiment! Brew two batches of the same beer and oak each with chips soaked in different spirits. Soak some oak in red wine and some in whiskey. Once the aging it done, can you detect any difference?
For sour beer, I soak the chips for 24 hours in plain water, dump the water and repeat 3 or 4 times. This removes a lot of the oak flavor but not all. Then I add to the fermenter along with a sour beer blend yeast. Once the sour beer is done (and it can take a long time depending on the style!) I remove the chips or cubes and store them in a cool dry place. Once I am ready to do another sour, I ferment the new sour with regular ale yeast and add the chips back to solution once primary fermentation is done. This inoculates the beer and starts the souring process. Typically, I will use about 6 ounces of chips for souring once all the oak flavor is gone from them.
Over the weekend I brewed the American Stout I posted about previously. It’s currently bubbling away in a happy primary ferment. Once it slows down I'll be racking the 5.5 gallons and splitting it between three little secondary fermenters. This will allow me to oak with three different toast levels of chips, tasting notes to follow in a few weeks. A couple of notes about the recipe: First, due to the amount of grain, this would be a great candidate for a parti-guile brew. Parti-guile is when you brew a second smaller beer on the second runnings of a big beer (this will be a topic in the near future). Second, I realized I left out mention of an extract recipe. You can try it by replacing the 15 lbs. base malt with about 10 lbs. LME and cutting out the Munich malt. Make sure to aerate well and use several yeast packets to ensure a fully fermented beer.