Can you brew a beer with a sourdough starter?

Yes! I’ve always wondered, can the yeast culture I spontaneously created deal with 10 litres of concentrated malt sugar? Or is it a step too far? Even if it ferments, will the product be tasty??

So, I set up a mini homebrew experiment. I brewed 10 litres of pale ale using exceptionally boring malt (pilsner) and a very low hop quantity (Citra at 60 and 30 minutes). The brew into two identical fermenters, the first half was fermented with a standard neutral commercially available ale yeast strain (US-05) and the second was fermented with my sourdough culture. I siphoned off 500ml of the brew and whilst the rest of the beer cooled, I added sourdough culture to the 500ml of beer. This fermented for 12 hours. I then tipped the 500ml of beer starter into the second fermenter and left them to bubble for 2 weeks.

At the two-week mark, both had fermented to the same sugar content, creating ~5% beer. These were bottled and saved for two more weeks to allow them to carbonate in the bottle.

Ok, I couldn’t wait two weeks so after one-week I sampled the beers. It had worked!! The sourdough made a delicious pale ale, not as crystal clear as the US-05 control, but more flavoursome. I periodically tasted both, in the name of science, over the next two months as the yeast continued to do its work in the bottle. Whilst the US-05 control stayed mellow and boring, the sourdough came alive as the wild bacteria started to outcompete the yeast and create an amazing Saison style beer.

I was so happy with the outcome; this is certainly the first of many. And maybe I’ll wrangle myself a minION to see what strains I have in there! My recipe is below, enjoy!