Friday, 19 September 2014

Brew Day: Sour Red Ale (plus Yeast Choice for Sour Beers)

As I've mentioned here before, I'm pretty interested in the links between the brewing traditions of Belgium and England, and in particular the effects that brettanomyces and LAB might have had on historical English stock ales.  I'm planning a couple more semi-historical brews in the next few months, but today I thought it would be interesting to try something completely different.  Rather than base my beer on a historical recipe, I came up with a pretty standard home brew recipe for a Flanders Red, and then substituted British ingredients for the Belgian ones.  The result looks nothing like any of the historical recipes for English stock ales I've seen on Ron Pattinson's blog or in his book (my main sources for this kind of thing).  There's too much crystal malt, no brewing sugar, and the hopping is pitifully low compared to the massive quantities in these old recipes.  It makes me wonder about how recipes for Flanders beers have changed over the past few centuries.  For instance, did they also previously rely on brewing sugars and smallish quantities of roasted malt for colour?  Presumably, if sourness was a goal, they might not have been hopped so aggressively---but then again, the hopping rates in lambics are on a par with these English stock ales, though typically with aged rather than fresh hops. Are recipes for porters and stock ales from the 1860s a good guide to the beers Eugene Rodenbach brewed when he returned to Belgium after working in England?  Was there a tradition of red and brown sour ales in the region before then?    I still don't know very much about the historical connections between the traditions behind these beers, but I'm sure some of this information is out there to find.

Anyway, I figured this recipe would produce a nice sour red ale, and I'm looking forward to the results, though I don't have any clear idea of how it might differ from a standard Flanders Red.  The general consensus seems to be that there is plenty of variation between malts from different countries---not just in the obvious cases (i.e. compare pilsner to Maris Otter), but also between things like crystal malts rated at the same colour level.  Perhaps this will result in subtle (or not so subtle!) differences in the final beer; or perhaps the sourness and funk will cover all of this up.  I don't have enough experience with different maltsters to hazard a guess here. I'm planning to use Wyeast 1318 for primary fermentation (much more on that below!), and then to use a small amount of a year old Flanders Red (perhaps along with some of its yeast cake) to inoculate the new beer as I rack the old one onto a blend of sour cherries and raspberries.

One thing I was thinking about while formulating this recipe was the difference that using an English yeast might make to the final beer---and on thinking this through, I came to the conclusion that I should be using English strains much more frequently when brewing sours.  I thought I'd indulge myself and type up these ramblings.  For those interested, the recipe for this beer is at the end of the post.

Yeast Choice and Sour Beer

I started with the thought there are two or three key things to think about when it comes to saccharomyces strains for sour beers:
  1. The amount of fermentable sugars they will leave for the lactic-acid producing bacteria.
  2. The precursors for brettanomyces-produced compounds they will leave in the fermented beer.
  3. The flavour contribution the strain will make to the final beer (assuming the flavours it produces survive the activity of the brettanomyces and bugs).
The significance of (1) is pretty obvious: if you want a sour beer, you need to make sure that the lactic-acid producing bacteria have enough fermentables to produce acid-levels to your taste.  One way of making sure there is plenty of sugars for the bugs is to use a strain of saccharomyces with a low attenuation rate for primary fermentation.  English yeast strains are obvious candidates here, since with the right handling they will finish with relatively high final gravities.  Of course, there are plenty of other ways to achieve the same result with more attenuative strains---mashing high, under-pitching, adding starches.  So (1) is inconclusive, but certainly doesn't speak against using an English strain.

With (2), however, things get more interesting.  Thanks to research by people like Chad Yakobson, home brewers are beginning to grip on the ways in which by-products of primary fermentation act as precursors for different flavours created by the ongoing activity of brettanomyces.  This set of slides from a talk by Chad Yakobson provides a good summary of some of his research; there's also information on this in Wild Brews and American Sour Beers; and there's more information in this thread on HBT.  

For now, the following will do as a rough and ready summary (based on my limited understanding of the science).  Phenols from the brettanomyces tend to yield the funkier flavours: barnyard, band-aid, medicinal, smoke.  Esters produced by brettanomyces tend to yield fruitier flavours: pineapple is a commonly-mentioned example.

With this knowledge, a brewer who wanted to produce a funky beer might try to increase the precursors for phenol production available to the brettanomyces.  There are various ways to do this (again, see Chad's slides), but the most relevant is by using a POF+ yeast, since these produce the 4-vinyl compounds that brettanomyces can convert into the relevant phenols.  The commonly used example of a POF+ yeast is hefeweizen strains, which produce distinctive clove phenolics---but many other commonly used Belgian strains such as Wyeast 3522 (Ardennes) and 3787 (Trappist High Gravity) are also counted as POF+ (according to a presentation I listened to by Stan Hieronymus from the 2014 AHA conference),  

So, using a POF+ Belgian strain will encourage the production of phenols by brettanomyces, increasing the levels of funkier flavours and aromas in the final beer.  What's more, since phenols seem to have an additive or synergistic effect, the phenolic character of Belgian yeast might also add to the overall perception of phenol-related flavours and aromas.

On the other hand, a brewer who wanted to minimize funky flavours might try to minimize these precursors, and an obvious way to do this is to use a less phenolic yeast strains: lager strains (used by New Belgium), the Chico strain (recommended by Jamil Zainasheff)....or an English strain.  

What about the other side: the fruitier flavours associated with esters?  Based on what I've been able to find out so far, the precursors for these are organic acids which come from a variety of sources, including the activity of enterobacter in spontaneously inoculated wort, dying yeast cells, and fatty acids in aged hops (all relevant to lambic production).  I haven't been able to find any evidence that esters themselves might provide the relevant compounds in a manner usable by brettanomyces, so that an ester-producing English strain might also be a source of precursors that result in some unique brett-derived esters.  The plausibility of this thought might be obvious to someone who actually understands the science behind all of this, but I do not.  What does seem to be true is that esters also have an additive or synergistic effect, so that at the very least, the combined ester production of the saccharomyces and brettanomyces might increase the overall perception of fruity flavours in the final beer.

Of course, this could easily back fire on you.  Just as too many phenols can make a beer taste like band-aids or medicine, too many esters could leave you with a beer that tastes like nail-polish remover or solvents.  Eugh.  So in both cases, a balance is required, especially if you're adding brettanomyces.

How to put this information to use in chosing a yeast strain?  Well, it depends what kind of beer you want to brew.  There are plenty of threads on HBT where people ask how to brew the funkiest beer possible.  A good answer would be: use a POF+ yeast, and take other steps to encourage the production of phenols. But when I envisage the kind of sour beer I'd like to brew, I think of something characterised by soft fruitiness with a low-level but definite funk in the background.  English yeast strains might be a great candidate for producing something along these lines.  Even if they don't lead to new esters from the activity of the brettanomyces, they might still produce the right levels of fruitiness and funk after secondary fermentation.

What about (3), the contribution the saccharomyces makes to the flavour profile of the final beer?  Since brettanomyces has a tendency to mix up all the flavours produced by primary fermentation, its hard to predict how much of this will survive.  But when I was formulating this recipe, I had in mind the gentle and balanced fruitiness that is produced by something like Wyeast 1318 (London Ale III).  This is one of my favourite strains, and besides its soft profile it also has the interesting quality of leaving a slight perceived sweetness in the finished beer that seems to be independent of the final gravity (i.e. if you compare it to other strains fermenting identical wort to the same F.G., it will still seem sweeter---but the sweetness isn't the cloying kind that comes from unfermented sugars).  If any of that flavour profile survived into the finished beer, it could make for a phenomenal Flanders Red!  

Of course, if the brettanomyces accentuated the estery flavours of a strain, or even produced new flavours along the same lines, even more possibilities would present themselves.  Imagine the stone fruit esters produced by something like Wyeast 1469 (and other strains of English origin) dialed up against a background of sourness and light funk. I think that could work really well.  (On the other hand, if it dialed up the banana flavours that Wyeast 1469 sometimes spits out, it could be pretty gross...)

Well, enough of my ramblings.  This is all a roundabout way of saying that I'm going to start using English strains in any sour beer that is not a saison or berlinerweisse or the like from now on!


Measured O.G: 1.054
Measured F.G:

Mash: 153.5°F:


39.6%  Paul's Mild Malt
26.4%  TF Golden Promise
18.5%  TF Pearl
7.9%  Medium Crystal
3.5%  TF Dark Crystal II
3.5%  Torrified Wheat
0.5%  Black Patent


EKG          60          20 IBUs


Wyeast 1318


  1. Very cool observations. How did this go for you? You mention the primary yeast, but didn't include the subsequent souring and funkifying additions... what regime did you follow?

    Looks like a nice recipe. I'm following something similar which is an amalgam of an english old stock and a flemish red / oud bruin, which I will sour and put onto 10 pounds of blackberries I picked last month. Here's my recipe:

    8 70% Golden Promise
    2 17% Munich (20L)
    1 9% Caramel/Crystal Malt - 60L
    0.25 2% Belgian Aromatic
    0.25 2% Chocolate (US, 350 SRM)

    20 IBUs Goldings

    Currently debating my yeast choice and souring regime. I may just sour in the kettle to the right level, boil to kill the lacto, and then ferment out with an English ale yeast. Possible a complementary brett addition to increase complexity, but I'm worried the brett will finish it out too dry.

    Would love to hear any thoughts you may have. Happy brewing!

    1. That recipe looks great to me. I've never tried kettle-souring, but one thing you might want to look into is how well English yeasts perform in acidic wort. I usually do a clean or mixed primary, so that's never come up.

      I've never seen super-attenuation in beers I've brewed with 1318. They usually finish between 1.004-8. But it can be hard to predict how mixed fermentations will go.

    2. Yes, it's a great point. I have tried to find info on the pH tolerance of different yeasts but there doesn't appear to be much out there. Another option is just to split the wort, ferment separately, and blend later, but I'm too lazy and don't want so much control. It will be an experiment in pH tolerance of different yeasts--if one strain doesn't work I'll try pitching another.