Sunday, 27 July 2014

Brew Day: Nineteenth Century Keeping Porter

IMG_1897For the most part I’ll be back to brewing English beers for the next few months, but that doesn’t mean I won’t be playing around with brettanomyces and lactic-acid producing bacteria.  These days beer drinkers who know what brettanomyces is probably associate it with Belgian style beer, but there was a time when many of the best English beers would have undergone a secondary fermentation by brettanomyces and perhaps other organisms.  Consider, for instance, the following quote from N. Hjelte Claussen (which I got from Mitch Steele’s book on India Pale Ale):
“In English breweries as well as anywhere else, the primary fermentation is carried on only by Saccharomyces, whereas the secondary fermentation of the typical English beers, as being due to Brettanomyces, essentially differs from those secondary fermentations on the Continent.  In other words, the action of Brettanomyces is absolutely necessary to bring English stock beers into proper cask and bottle condition, and to impart to them the peculiar and remarkably fine flavour which in a great measure determines their value…. Hence it is evident that the secondary fermentation effected by Brettanomyces is indispensable for the production of the real type of English beers.”
If you dig around in Ron Pattinson’s posts at Shut Up About Barclay Perkins, you can find lots more interesting tidbits.  For instance, it seems that British brewers resisted the introduction of pure yeast cultures (i.e. the single strains we’re used to using today) for much longer than the majority of brewers in mainland Europe, in part because they found beers brewed in this way lacked the character they expected from secondary conditioning.  In my earlier post about Yvan de Baets’ essay on saisons, I quoted one of his sources (Van Laer) questioning whether the introduction of single strain fermentation should be seen as a mark of progress.  It seems that, for a while at least, British brewers would have agreed with him!
I’ve found some more interesting material, but I’ll save that for another post.  My plan, as of now, is to brew a series of beers based on historical recipes from Ron and other sources (plus a couple of amalgamations of my own), and then age them all with brettanomyces and possibly lactic-acid bacteria.  The first, which this post is about, was a recipe for an nineteenth century keeping porter (i.e. a porter that was vatted at the brewery for many months before being sent out for sale).  In the next month, I’ll probably brew an India Pale Ale, along with a couple of stock ales as well.
I’m not in any position to give a summary history of porter brewing (though its a fascinating topic, and worth reading about).  Vatted porters were aged at the brewery where they underwent a secondary fermentation, most likely induced by organisms resident in the casks and vats they were stored in.  Martyn Cornell gives the following account in Amber, Gold, & Black:
“Long storage in wooden vats, with the inevitable infection by wild Brettanomyces yeasts and lactobacillus bacteria, would have produced a ‘stale’ porter that was vinous, tart, and almost still.  For drinkers who wanted something livelier with a good head on it, the porter brewers sent out fresher, milder, newer-brewed, more carbon-dioxide-impregnated beer alongside the matured, flat, stale porter.  The mild and stale porters were then mixed at serving, or drawing, in the pub to the customer’s taste…”
To mimic this I will brew another beer in 9-12 months, and blend both together at serving. The recipe I used as my starting point today was for an 1831 Keeping Porter from the Truman brewery (you can find it in Ron’s book).  Ron’s notes mention that there were two types of porter brewed, a keeping and a running version.  The recipes were the same, except that the keeping version was much more heavily hopped.  The two beers were blended back together at a ratio of 1:2 keeping to running before sale.  So that provides me with an idea of what to aim for.

I had to take some liberties with the recipe, which make this more of an “inspired by” brew than a real attempt at a historical recreation.  The biggest difference, which scuppers any attempt at historical accuracy, is the character of the brown malt I have available to me.  I used Thomas Fawcett brown, which is a nice malt, but very different from what would have been used in this recipe (you can read a bit about history of brown malt here).  Other home brewers have had some success making their own, but it requires an open flame, which rules out attempting to make it in the only outdoor space I have: my wooden fire escape. 

The other slight modifications (besides a single-infusion mash) were in the malt and hopping.  Rather than use the single base malt listed, I went with a blend of 2-row and mild malt.  It was what I had on hand.  The hopping rates for the old beers are insanely high, even when you consider the fact that its all English hops that had around 4-5% AA (in fact I suspect that this one used older hops whose alpha acid levels were lower still).  The EKG I have on hand have 5.9% alpha-acids.  Hopping at close to the rate listed in the recipe puts me way above the 116 IBUs, so I decided to just shoot for this IBU number instead.  I suspect that the sheer volume of hop matter in the kettle affected the flavours of the final beer, so to increase the amount used I made the 90 minute addition smaller so that I could increase the volume of hops for the 60 minute addition.

Primary fermentation will be completed by some recently cropped Wyeast 1469.  I’m also fermenting the beer in one of my old saison/brett buckets, so it might pick up something from the scratches there. For secondary conditioning I’ll pitch some White Labs Brett C.; I’m also considering blending in a small portion of an Oud Bruin I brewed with Wyeast’s seasonal blend.  This contains Lactobacillus Brevis, which is supposedly more hop-tolerant.  Frankly, with the hopping levels what they are, I doubt that this will have much of an effect; but I want to avoid pediococcus in this beer, because I’ve heard speculation that it encourages super-attenuation by brettanomyces, and I’d like to prevent that if possible (Brett C. seems to be, at least sometimes, less attenuative than other strains in secondary).

Tasting notes: #1, #2.

Recipe:
Measured O.G. 1.060
Measured F.G.
ABV.
Mash: 154°F
Malt:
44.6% 2-Row
29.0% Mild Malt
24.6% Brown Malt
1.9% Black Malt
Hops:
EKG 85min 47.0 IBUs (40g@ 5.9%)
EKG 60 min 70.0 IBUs (60g@ 5.9%)
Yeast:
WY1469 

3 comments:

  1. Great to see other brewers making keeping porters. I still have a batch of porter I made from my own brown malt that has been aging in a secondary for almost two years now with brett c and lacto. It has been fun to see how the flavor changes over time. Luckily, I've not had any problems with Pedio or sourness. Cheers.

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    Replies
    1. Cheers Will. I was looking over your blog the other day to see if you'd posted any updated tasting notes for the beers you aged. How have they changed over time?

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    2. One of these days I'll get around to kegging it and doing a proper tasting. I can say that the smoke character from the wood kilned malt has totally dissipated and what's left in its place is a slight 'woodiness.' Also, the brett and lacto are more subtle than one would think after two years aging. Less characteristic brett flavor and more wine and port type flavors.

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