Today I ‘racked’ some home brew (from a kit). At the top of the primary fermentation container (aka ‘the big bucket’) is a whole lot of brown goo.
That brown goo is the source of modern test tube yeast which extracts one strain and then replicates it in sterile conditions.
To make your own ‘beer bread’, simply extract some of this scum using a spoon, finger, whatever into a bowl, add flour until the consistency is about 65% hydration (typical dough moisture content) and wait a while.
At room temperature you won’t have long to wait. Then you treat it as you would any starter.
I have found that when using a fresh batch, what you will have is an EXTREMELY vigorous starter culture which emphasises yeast over bacteria meaning you will get HUGE rises. Timing of course is important, but this depends so much on temperature, flour, humidity, timing of your method and so forth. Basically, it’s more like dealing with test tube yeast.
For myself I use ‘Method #2’ which involves building up the starter the day before baking to between 20% (in summer) and 38.2% (in winter) of the final dough weight and adding it in on Bake Day morning about 6 hours before baking (about 2 hours to soak and a couple of stretch and folds, then shaping and about 3-4 hours proof time). Method #1 adds in a smaller starter percentage – around 3% summer to 8% winter – letting the dough slowly ferment overnight so in the morning there is only shaping/proofing beginning about 4 hours before baking. Because the beer ferment culture is so dynamic, I find it best not to leave it overnight. No matter how little you put in, especially in warmer summer months if you are not retarding in a fridge, it gets ahead of itself.
Note on retardation in fridge: if you have a cool cellar, that is best. A fridge is fine. I just personally don’t have a fridge big enough to retard all my dough, though my second, and bakery, fridge could handle about 48 loaves and indeed I used it for this last year. But I got tired of having half my doughs retarded and the other halves not and have decided to learn how to work with higher temperatures without too many mechanical tricks. I now use the fridge to store the starter between bakes, and am extremely grateful because I don’t have to keep refreshing it every 7 hours or so to prevent over-population and then die-offs of part of the starter populations. But if I baked every day, frankly I wouldn’t need the fridge. It’s a good technique, though for home bakers. You can manage the fermentation more easily (if you like slow techniques like mine) which makes timing more forgiving and greatly deepens the flavour, but also you get much better oven spring. I think the yeast has been held back in the fridge and then goes wild as it warms up, but perhaps it’s the opposite: the bacteria get suppressed in the cold so the yeast predominate. (I read somewhere what it is exactly but have forgotten, sorry!)
Personally I like rye sourdough better than beer fermented. But the beer fermentation is very interesting especially with whole grains because you can get really monstrous rises even with whole grain doughs.
I’ll be making a whole grain whole wheat batch and a Red Fife White batch tomorrow and will take pictures of the results, posting them with this entry.