When I first started in 1995, the brewery was part of the Firestone Winery. We were getting rid of hundreds of wine barrels. A lot were being turned into planter boxes, and I actually spent time convincing the cofounders that it was a bad idea to make our first beer in retired wine barrels. There was no market for wild or sour beers at that time, and we didn’t want the microflorae. I convinced the owners that if we were going to make “clean” beer aged in wood, we needed new barrels that had never been used. Fast- forward 22 years, and we have a whole program that uses wine barrels, the same kind that we got rid of all those years ago. Funny how things change.
Wine barrels are a vessel, but they are also an ingredient. A wine barrel is a living environment of microflorae that helps us create the beers that we want to taste. When we brew with wine barrels, we’re not always looking for the characteristics of the wine that was once housed inside. If we wanted something that was heavy on the influence of the fruit, we’d get juice, must, crushed skins, or the raw ingredients; that would impart true wine character. But when we ferment and mature beer in wine barrels, really we’re looking for the characteristics of the microflorae and oak.
In selecting barrels, a couple of things are obvious. If the inside of the barrel smells like vinegar, you’re likely going to get a beer that has those aromas and flavors, and that’s not always desirable. Also, in California, there’s a beetle that likes to bore into the wood of barrels, particularly those that wineries have stored outdoors. We don’t want to bring those into the barrel room, so we try to keep away from barrels like that. A visual and sensory inspection is important. The barrel may have been left dry for some time, so you may need to rehydrate the barrel, swell it up and stop any leaking.
We are moving toward more neutral oak in our wine barrels so that our bugs have a nice and consistent habitat in which to do their things, and less oak extraction. There is a relationship between the terroir and the barrel that is a fermentation dynamic. You can use a wine barrel to make just about any kind of beer, but you really need to think beforehand: what’s the goal? You could make a helles, but why? For us, the goal is to impart some acidity, wild-yeast characteristics, or a little oak profile that a wine barrel might have had before it was retired. Wine is generally in the 12 to 14 percent ABV range, so you have microflorae that survive in a way that they won’t in high-proof spirits barrels.
I’m sometimes asked why use a barrel at all, with all the advances or products available? I think there is a sense of romance to it, some adventure. And a barrel breaths! In the retired wine barrels, Acetobacter, lactic acid bacteria and even Brettanomyces can survive after they are empty. That will influence the character of beer inside, for better or for worse.
Usually, we kick-start our barrel fermentations with a few of our mixed cultures (I call them cocktails). We inoculate after racking into barrels (after primary fermentation). This helps us get to where we want to be with the finished product.
But there are still some things that we don’t know; we don’t understand all the reactions happening in the barrel over months or years: There are many reactions taking place in the barrel that produce different flavors and aromas. We’re not even aware of all the microflorae that are in the barrels. We know a handful of them, but there are some we have not identified. But it all becomes part of the habitat of the barrel and the beer. Eventually when it’s ready, we can decide whether or not we like it, whether we want to blend it, or whether we have to let it go. Those are the options. One must be patient, have time for trial and error, and be willing to dump it if it doesn’t live up to the standards and goals you set.