Oak Barrel Experiment

by Jim Mosser, May 1995

This was posted to Homebrew Digest #1747, June 2, 1995, by Terry Terfinko.


I have had an interest in aging beer in oak barrels for some time. Not having access to a barrel, I convinced Jim Mosser, owner of our local homebrew shop, to get a barrel and conduct some research. Over the last 3 months Jim conducted some experiments and documented the results. Here is a copy of his documentation.
--Terry Terfinko


Oak Barrel Experiment

I'd like to take a moment to address the research end of the experiment. First of all, I have never encountered as much misinformation or disinformation about any other aspect of brewing than with these barrels. I've concluded that it's impossible, in many cases, to separate the good info from the bogus info. Some of the info almost seems to be generated by ego alone: i.e. "It's true because I say so," etc. (that's a general statement only, folks!). Anyway, I finally decided to forego all of the hoopla, and simply plug ahead on my own. Having done that, here is a general chronology of what I've done to date. About the experiment itself, I focused totally on the aging side of oak barrel use, and not dispensing. An experiment with priming and dispensing might happen at a later point, but I'm not really of the opinion, at this time, that it's a practical idea.

First, the barrel. The one I chose to work with was a 3 gallon barrel made of American white oak, which was charred on the inside. It was built in New England, and was brand-new. I went with a three gallon barrel because I figured that, since the smaller the barrel, the higher would be the ratio of oak to beer. In other words, if I could make this whole thing work with a 3 gallon barrel, a 5 gallon barrel would be even easier.

The first order of business was to brew a batch of beer. To this end, I chose a pre-hopped beer kit (Arkell's GWR Strong Bitter, manufactured by EDME), adjuncted with one half pound of dry malt. The yeast used was a re-propogated bit of Chico ale yeast. I opted for simplicity, because I wholly expected that I might lose the batch of beer for one reason or another. This batch went well enough, and spent nearly four weeks in primary and secondary fermenters, at which point I prepared the barrel. First, I filled the barrel with water. It leaked a bit, but after a few hours the wood swelled up, and the leakage stopped. So far, so good. I then emptied the barrel and refilled it a couple of times, just to clear out any excess bits of loose charred matter.

At this point, I filled the barrel with hot water and a substance called Barokleen, which is essentially a blend of soda ash and lye. This stuff stayed in the barrel for three days. I then repeated the process, as this was supposed to leach tannins out of the oak, and I'm sure many of you have heard about perported high tannin levels in American white oak. Anyway, after all of this, I soaked and rinsed the barrel with cold clean water five or six times over the next few days, always leaving the barrel full. I then sterilized the barrel with a blend of sodium metabisulfite and citric acid (following the instructions on the package), and re-rinsed the barrel about a half- dozen times after that with clean cold tap water. Finally, I was ready to fill it with beer. I simply siphoned directly from a carboy, put a stopper and airlock in the bung hole, crossed my fingers and prayed to the beer gods for good fortune.

From the get-go, I drew a small amount of beer each day, to monitor the flavor. By day three, I began to notice the oak for the first time, and it grew in intensity with each day. At day six the beer had developed a marvelous balance, but by day eight it was becoming overly oakey in character. Finally, I pulled the beer on day ten, and bottled it. I simply rinsed the barrel out twice with cold water, and let it sit, full.

Meanwhile, I had brewed a second batch of beer, this one a barley wine. I had read more than once that with new barrels, it might be advantageous to use high gravity beers the first couple of times, in order to leave a beer "imprint" in the barrel. This beer was another kit: EDME barley wine, along with a 1kg can of Morgan's dark crystal Master Blend, and a re-propogated bit of Wyeast Scottish ale yeast. The starting gravity was 1.072, and I gave it a two week primary fermentation in glass. I prepared the barrel with the sodium metabisulfite and citric acid as before, and rinsed it five or six times. I then racked the barley wine into the barrel. After a couple of days, I dry-hopped the beer with 1/3oz of Kent Golding pellets.

After two weeks, the beer had developed an oak flavor, but not nearly as oppressive as the previous batch. Furthermore, that first batch of beer (the Arkells), after a month in the bottle, had begun to lose it's oakiness to the point that it has become very drinkable. This has caused me to conclude that it's probably OK to let the beer sit in the barrel, even if the oak flavor seems to reach an excessive point, because that flavor does recede somewhat with aging. Now, I have brewed a batch of imperial stout (O.G. 1.065), and that will be the next beer to get the oak treatment, once I've decided to pull the barley wine.

Finally, my conclusions to date. Well, as I expected, the first batch was a little harsh, but certainly drinkable, and it has improved in the bottle with age. The second batch is maturing beautifully, and the oak flavor seems to have reached a peak and stayed there. I have experienced no infection problems whatsoever, and, unless I have overlooked something, it appears at this stage that American white oak barrels are nothing to be afraid of, with regard to conditioning beer. The oak flavor, of course, is, regardless of strength, a matter of personal preference. Frankly, I have never tasted anything quite like it, and I am becoming rather fond of it. Since it's a good idea to keep these barrels full at all times, I'm simply going to keep putting batch after batch of beer in there, and see what happens over time.

For all of you who have contacted me about this subject, I want to express thanks for your interest, and also your individual suggestions and offered information on the subject. It's all been very helpful. For anyone interested in any experiment updates from this point on, I can be reached at 1-(800)-900-8410. I also want to thank Terry Terfinko personally for goading me into this experiment. I hope this information will be of value to some of you. The experiment's been a lot of fun, and I've also learned a bunch. Well, that's it for now. To all of you, Good Brewing!

Jim Mosser