Enteric Bacteria in Lambic Beers

[brwagur]

Was poking through the links on The Mad Fermentationist and came across and interesting overview on lambic brewing. The most interesting section was concerning the role of enteric bacteria in flavor development.

Due to the fact that these bacteria are alcohol and pH sensitive they would probably not survive in the yeast cake and so would have to be reintroduced at the start of each batch.

Does anyone here do as suggested and leave your fermenter open on the kitchen counter for 24 hours? I found the information to be logical and yet had not heard it anywhere before.

Anyone have any additional input on the matter?

 

[dantheman13]

There have been a lot of open fermentation projects from people over the years, many of them documented on blogs. I don't have a list readily available, but you should be able to find them. I plan on giving this a try for the first time this winter.

 

[mnick12]

I have a "lambic" that was inoculated with a wild culture and ecy19. It was roughly 58% flaked rye 40% pils and 2% caramel rye. Primary looked like a normal brett fermentation, but after aging for a while it had some odd smells coming from it. About 6 months in it starter getting a weird sort of fecal character which was pretty off putting. Now at 10 months its really different, much better and more of the classic funk with some weird fruits notes.

Most eneteric bacteria like e coli and what not reproduce a lot quicker than sach or brett. So if are trying to inoculate some wort with some I would take some measures to keep them in check, like a lot of hops or an acidic starter ( like I did).

 

[roink]

I could not open the link but:

Jeff Sparrow states in his "Wild Brews" that enterobacter produce unfavorable aroma and flavor compounds including vegetal, smoky, moldy and diaper.

While enterobacter is found in almost all lambics in an early stage, lambic producers usually try to minimize their presence.

The Mad Fermentationist let his wild-starters alone for three weeks after inokulation. Enterobacter should be dead by this time thanks to low pH and alcohol. Only then did he taste and use them.

 

[Oldsock]

For my most recent "lambic" I allowed about 24 hours of open cooling in the kettle before transferring to a carboy and pitching a starter built-up from a few choice bottles of 3F gueuze. It was very sulfur-diaper young, but turned out beautifully with two years of aging. Brett can turn many "off" fatty acids into wonderful esters. This process is actually pretty similar to a lambic brewery, except rather than pitching the next day per se, the cooled beer goes into barrels that house the house culture.

 

[metic]

I'm in the middle of a spontaneous fermentation experiment at the moment, and have been reading up on the fermentation cycle of lambics as a result.

Oldsock has already mentioned that enterobacter will produce fatty acids that might serve as precursors for the esters produced by brettanomyces. Reading through Wild Brews again I was also struck by the claim that the activity of enterobacter in the early days and weeks of fermentation might shape the rest of the cycle, since the enterobacter will consume amino acids in the wort before the saccharomyces get a chance to use them. This will slow down the growth of the yeast and limit their ability to ferment the wort---Sparrow gives O.G.s of 1.022 after 3-4 months, and 1.012 after about 8-12 months. That means that there is lots of fermentable sugar left when Lactic Acid Bacteria become the dominant organisms and take over fermentation. It also means that brettanomyces doesn't become active until relatively late in fermentation, since it grows even slower than saccharomyces.

It got me wondering how the different cycles of fermentation in lambics vs. inoculated homebrews affect the final products. It seems like the microbial populations at any given point in fermentation will look pretty different, and that you'll have different kinds of organism responsible for different parts of the fermentation. For instance, I've never had a beer with an O.G. between 1.040-50 be as high as 1.022 after four months of secondary fermentation, nor have I had one be as high as 1.012 after a year.

Not going anywhere in particular with this, just something I was thinking about while checking on my spontaneously fermenting wort this morning!