I like sour beers, so I wanted to try making one, but I wanted to avoid infecting my equipment. I’ve been told that the bacteria you use in a sour beer can get into your plastic and rubber fittings and it’s nearly impossible to get it out.
One way to avoid that problem is to sour some wort first, then boil it to kill the bacteria.
Some people use grain to sour the wort. To do this you just make a small batch of wort, drop some grain in and allow the bacteria that lives on the husks to get to work. I’ve been told that method works, but I hear it’s a pretty smelly process.
A while ago I decided to try my hand at kombucha. You can read a little about that on this page.
Kombucha is fine. I don’t like sweet drinks, like soda, and I try to stay away from too much caffeine, so a batch of decaf kombucha can be nice after work. But I’d rather drink a beer, so I decided to experiment with souring some wort with my kombucha mother and using that in a Belgian-style sour.
Here’s how I did it. These procedures are designed for a 3-gallon batch. I did 3 gallons because I do kombucha in a one gallon jug, and 1 gallon of soured malt in a 3-gallon batch seems to be about the right ratio. Your mileage may vary.
To start you have to have a batch of regular kombucha, which means you’ll need a scoby. You can buy one or you can grow one. Here’s a good page about kombucha.
Assuming you’ve got all that straight, here’s how you make Kombucha Sour Ale.
On the day you’re ready to bottle your kombucha, boil 1.5 cups of amber DME in 13 cups of water and let it cool. When it’s cool, reserve 2 cups of your kombucha and bottle the rest. Inspect your scoby to make sure there’s no black spots, rinse it off and set it on a clean plate.
Rinse out your kombucha jar, add the reserved two cups of kombucha, add the 13 cups of malt you boiled and cooled, then add the scoby. Cover it with a cloth and let it sit for 2 weeks.
On brew day, prepare whatever you’re going to put on your scoby next — whether that’s tea or more malt. Remove the (now soured) malt from the kombucha jar and reserve two cups. You’ll use those for your next batch of kombucha.
Pour all the rest of your soured malt into your kettle then proceed as if you’re doing a very simple extract recipe.
4 pounds amber DME
1 oz. Saaz (60 min.)
1/2 oz. Saaz (30 min)
1/2 oz. Saaz (10 min)
Irish moss (10 min.)
Boil for an hour, cool, add water (if necessary) to get to 3 gallons and pitch Belle Saison Ale Yeast. Ferment and bottle or keg like any other beer. (Since you boiled your soured wort, there’s no risk of infection in your kegging equipment. Also, if you choose to bottle remember to adjust your priming sugar for a 3-gallon batch!)
I’ve tinkered with this recipe a few times — sometimes using a little more DME, sometimes leaving it on the scoby a little longer. But each batch has been very good.