October 5, 2010 - 10:05am
Brewers skimmings
My friend works at an artisanal brewery and he has just brought me some of the skimmings from the top of the mash tun. I asked for them because I had heard that that is the traditional way that bakers got their yeast. He just showed up unexpectedly and now I have around half a litre of the stuff and no real idea what to do with it. Any suggestions? Can I feed it with yeast like a sourdough starter? It smells lovely and beery. The beer it is from is a stout-style beer so it smells of the roasted malt so I was thinking of maybe a rye loaf? Any ideas gratefully received. Thanks!
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this is a time sensitive question and no one has yet weighed in - I'll give it a try. I'll warn you, I've never baked with this substance, but am giving reasoned speculation.
This is real "barm" and yes, was traditionally used to leaven bread. It was not cultured separately (the way we do sourdough) but was continually harvested from the brewing process.
I would not try to turn it into what we know as a sourdough starter. Why? I've recently been convinced that eventually what you would end up with after all the various wild yeasts/bacteria/etc. fought it out would be no different than if you just used flour and water - unless - you refreshed the thing daily with the barm, and that would be a shame.
But I would either use this as the liquid in a 100% hydration pre ferment and then try to bake bread with no added yeast, or use it as all of the liquid in a straight dough formula.
If it actually were me (and it is not, I know) I would use my 65% hydration baguette formula and use this as the liquid in the pre ferment. Why (again)? because I know how that formula acts like I know my name and I could use it as a good baseline to understand the impacts of using this particular type of yeast. I would then consider any variations that I saw along the way and try to understand the best way to change things to use this lovely barm.
Rye is also a good idea if you have a mixed rye/wheat recipe that you know well. I would not use the barm on its own for a 100% rye bread.
Hope someone can weigh in with better advice, but this is the best I can offer.
Happy Baking.
If the skimmings came from the mash tun, then you have the wrong thing. The yeast is not yet in the beer at that stage. What you need is the skimmings from the fermenter, which is where the yeast activity starts.
Porkbutter is quite right. The mash's purpose is to use time and temperature to control the extraction and breakdown of complex sugars, e.g. maltose, into a balance of simpler sugars the yeast can use. When done, the sweet wort is sparged to arrive at the desired specific gravity, and moved to the brew kettle where it is boiled for an hour and a half or more. The boil sterilizes the wort, causes proteins to clump or form long chains, and extracts hops resins for flavor and aroma.
After the boil, the hopped wort is chilled as quickly as possible to precipitate the proteins that can cloud the beer and produce off tastes.
Now, the yeast is pitched, and the wort is roused, much as we stir a sour dough seed to incorporate oxygen for the little beasties.
Assuming an ale yeast (top fermenting), you want the skimmings from the second or third day, after the ferment has settled a bit. At first, that big ragged meringue looking foam will have a lot of dead yeast, and there is a lot of oxidation damage. The brewer skims that stuff like the citizens of Chicago vote, early and often, as it can cause off flavors. Later skimmings are OK, containing healthy, robust yeast, under the protective layer of CO₂.
If it's a lager brew, the better choice for yeast is the sediment from the secondary ferment.
Brewers show as much love toward their yeast culture as any baker ever did for his sourdough. You will probably need to grow your yeast to get enough to use as a vigorous starter. I've not tried to grow beer yeast for a bread starter, but I'll assume you don't have a ready supply of sweet wort to feed it. In that case, I'd pre-soak some rye flour, or maybe chops, to let some enzyme action break down the starch a bit, then boil to sterilize. Beer yeast is not as robust as wild yeast, and the aceto- and lacto-bacillis would make the culture way too acidic.
Good luck, sounds like a fun experiment.
You are knowledgeable, Gary. Do you brew your own beer?
Karin
Thank you, Karin,
I did brew several years ago, but moves meant kitchens too small for the large paraphernalia needed for mashing, sparging, boiling, primary fermenting, lagering and bottling. :(
Maybe my baking is a substitute for brewing.
[ot]Did you take your nick in homage to the Hanseatic League of the late middle ages? I'm under the impression you're from that area.[/ot]
cheers,
gary
Yes, Gary, I'm a Hanseat from Hamburg - Hamburg's official title is "Free and Hanseatic City".
Karin