Bet you can tell what I've been reading this week. That's right, "The Art of Brewing" by David Booth. Fascinating little book, it really is.
If you thought that spontaneous fermentation was just a Belgian thing, think again. It occurred in Britain as well. Though the vast majority of beer was produced using top-fermentation, spontaneous fermentation was practised by private brewers in some counties.
"The Spontaneous fermentation is never employed, except for strong Ale. Weak worts would probably run into acidity before the vinous fermentation could take place. In this country, the strongest wort (that of the first mash) is well boiled with a very large proportion of hops, which are judged necessary for the preservation of beer that is to be so long kept. When sufficiently boiled (which is judged by its breaking pure, as described at p. 40, Part II.), the wort is turned boiling-hot into the casks, without separating it very nicely from the hops. The casks that we saw were butts, standing on end, and containing about three barrels each; and the bung-hole in the top was, in the first instance, either left open, or slightly covered, at pleasure. In about forty-eight hours, less or more according to circumstances that are indeterminate, a froth is seen to issue at the bung-hole; and this working, which never carries a head of yeast, continues during eight or ten days, when it gradually subsides, leaving the surface of the liquor covered with a white crust. At this period, the beer will usually be found, owing to the diminution of heat, to have shrunk into less space, and to have left six or eight inches of a vacuity in the cask. The cask ought properly to be filled up; but for want of spare beer this is often neglected: and it is said that the liquor keeps equally well, being defended from the atmospheric air by its crust. For the first three months, the ale, though pure, is not reckoned fit for drinking. It has a rank bitter flavour, which our informant ascribed to the seeds of the hops which lay steeped in the cask: but in five or six months that flavour goes off; and it becomes fit for drinking, though it is usually kept untapped for a twelvemonth." (Source: "The Art of Brewing", by David Booth, 1834, Part III page 14.)
Any adventurous home brewer fancy taking a shot at that? I thought not. I know I wouldn't. All that time you'd need to invest for something that could (probably would) turn out undrinkable.
I'm deffo going to give spontaneous fermentation a go at some point. I could be living on a microflora goldmine and I'll never know until I leave a bucket of wort out in the garden overnight.
ReplyDeleteBut it's the wrong time of year for it at the moment.
I left some boiled wort out for a week and it didn't ferment, but did grow two different kinds of mould.
ReplyDeleteA week will do that, I'd say. You just want it inoculated quickly and then left to its own devices in more conducive surroundings. Like a cask.
ReplyDeleteOn page 38 of Booth, he states that if a spontaneous fermentation is properly done, the beer will not be sou or taste improper in any way. To do this, you need to do two things that, he notes, are incompatible with modern (1830's) commercial brewing: you need to make the beer strong and you need to let it mature a long time. He states that some country house beers are made in this way and refers to personal experience as well.
ReplyDeleteSuch ferments were much slower than one assisted by a dose of fresh yeast. Distillers in the old days sometimes had resort to wild ferments, especially at the start of a distilling season when there might be no fresh yeast available, even from a competitor.
As for molds, Booth speaks of a white crust that forms on the beer and I wonder if this might have been a benign mold of some kind, perhaps akin to the flor generated in sherry production.
Gary
Beer Nut, I'm first in line for a bucket of your spontaneous brew.
ReplyDelete