Farmhouse Ales I: Mixed Fermentation

I’ve already mentioned several times how much I like Yvan de Baets contribution to Farmhouse Ales.  Over the course of the essay a complex picture emerges of the character of old saisons, and the ways in which ingredient choice and brewing process contributed to it.  Since it continues to shape the way I think about my home-brewing, I thought I’d dedicate a series of posts to this chapter, along with some of the beers I’ve brewed that have been inspired by it.

One thing de Baets emphasizes is the inevitability of a mixed fermentation, and the various desirable characteristics this gave the beers.  Although the brewers pitched saccharomyces, a spontaneous culture of wild yeasts and lactic acid producing bacteria would almost certainly evolve alongside the top-fermenting yeast because of their brewing processes (e.g. “chilling wort in shallow coolships, fermentation and conditioning in unpitched wooden casks, and brewing on a farm”.)  As is the case with any fermentation, brewers were able to exercise some control over this culture by selective re-pitching and by controlling the character of the wort (e.g. exploiting the bacteriostatic properties of hops), but de Baets suggests that some contribution from a spontaneous culture was considered valuable.

Various reasons for this are mentioned throughout the chapter.  Here are some key ones:

• The lactic acid produced by bacteria “provided a natural preservative that lengthened [the beer’s]  life considerably”.
• The wild yeasts were highly attenuative, ensuring a dry and refreshing finished beer.
• These yeasts, along with the bacteria, produced various compounds that gave the beer a pleasing aroma, as well as a property de Baets calls “vinosity” (“complex flavours found in Jerez and sherry wines…includes a “wild yeast” estery flavor, some woodiness, and eventually an apple-like aroma coming from oxidative fermentation.”).  He cites Van Laer as stating that secondary yeasts “create rather high amounts of organic acids which slowly turn the alcohol into esters and cause the appearance of the wine-like taste characteristic of old beers”, and suggests that this vinosity and sourness was highly sought after (to the point where brewers would blend young and old beer together to achieve it---but that’s a topic for another post).

While the BJCP saison category does not acknowledge this side of the beer’s history, many American brewers have started to use mixed fermentations in their saisons to give the beers “a small ‘wild’ side”, no doubt in part under the influence of this book.  De Baets actually references older literature that questioned the way in which brewers had come to rely solely on fermentation by pure cultures, something that has been vindicated by these recent trends:

“It is certain that the introduction of pure yeasts into industrial fermentations does not constitute the crowning achievement of a system that is henceforth immutable.  It seems, for example, that if the application of the pure cultures method has improved the average quality of the beer, it has given us beer with less character then before” (Van Laer)

So the upshot of all this is that, done right, mixed fermentation has a lot to offer when it comes to brewing saisons.  The beer I’m going to post about today is one of my attempts to realize this.  Its based on  a pretty typical saison grist, fermented with Wyeast Farmhouse Ale (3726).  The “mixed culture” came in the form of this year’s Bug County blend (ECY20): I pitched ~10ml along with the saison yeast.

After primary fermentation, the beer tasted like most of the other saisons I brewed with 3726.  Based on my experience so far, I’m not so keen on this yeast as a sole fermenter: it gives off various fruity and white wine-like esters (perhaps because I fermented it at the lower end of its temperature range) which sound good on paper but come across as slightly sweet, and for me detract from the drinkability of the beer (Firestone Walker’s Opal reminded me of some of them).  So I was a little disappointed with the flavour profile when I transferred the beer to secondary with a gravity of 1.004.  I tasted it occasionally over the next 3 months, and although it developed a light tartness and some funk there was no major change.  Then, all of a sudden, at around the four month mark, it developed a notable sourness.  Since the gravity was around 1.001, I decided to bottle it to free up the fermenter.  I gave it a fairly light dry-hop with some Crystal (de Baets mentions this as a technique used to “rejuvenate” old beer) and bottled it in a mix of regular and heavy bottles.

At around five months the beer is still relatively young, and I expect it to continue to develop in the bottle over the next year.  I’ll make sure to post a few more tastings after this one.

Appearance: Hazy yellow bordering on orange.  Medium head that dissipates quickly.

Smell: Some of the fruity(pear?)/white wine character I get from my other saisons with 3726, but more subdued and mingled with sour (canned pineapple juice) and creamy (yogurt) notes. Light acetone if I really dig for it.

Taste: Light sourness at front and sides of mouth.  Fades to slightly sweet white wine flavours (pear again? nectarine?) and canned pineapple juice before sourness reasserts itself at back of mouth.

Mouthfeel: Carbonation still fairly low.  Creaminess that I think will develop into a more vinous mouthfeel.

Drinkability & Notes: This is a little one-dimensional at the moment, but shows a lot of promise.  The sourness provides a nice complement to the flavours I got from the Farmhouse Ale strain, balancing their fruitiness.  It is already fairly vinous, and I think this will improve with time.  The main thing I’m hoping for is a more nuanced aroma and flavour as the brettanomyces start to make a contribution.

 

Recipe:

Estimated O.G.	1.046
Measured O.G.	1.044
Predicted F.G.	1.000
ABV.	5.6%
IBUs	14.3
Mash:
	149°F	90 minutes
Malt:
40% Pilsner
40% 2-Row
10% Vienna
10% Torrified Wheat
Hops:
Crystal	60 min	14.3 IBUs	(15g @ 4.8%)
Crystal	0 min	0.0 IBUs	(28g @ 4.8%)
Crystal	Dry Hop	1.7g/l	(20g @ 4.8)
Yeast:
Farmhouse Ale (Wyeast 3726)	Bug County (ECY 20)