Stuck Fermentation? (If you say so)

[peebee]

Here's a fermentation trace to scare the willies out of many a forumite here:

To be honest, it disturbed me a little until I figured what I'd done. An FG of 1.036; that must be "stuck"? What I'd done was forget I was mashing an enzyme deficient diastatic brown malt (emulation) and mashed at an eye-watering 69-71°C. Not many B-amylases kicking about to start with, and 69-71°C saw them off pretty quickly.

I was aiming for an FG of about 1.027!


It's worth picking over a little (well ... it was for me) as it does illustrate some features of mashing and fermenting.

The "beer" is an attempt at recreating a historical "Stitch" based on an interpretation of a recipe in the "London & Country" publication of 1736. The interpretation is in CAMRA's Homebrew Classics "Stout & Porter". It's an Ale; that's really an "Ale" and therefore not a "Beer". But by that time Ale was competing with Beer and was encompassing hops. It was dark being made of 100% diastatic brown malt, but in a hundred years was to be displaced by paler malts to become the "X-ales". The X-Ales were destined to displace the highly popular Beer of that time ("Porter") and by WWI was ironically becoming dark again as "Mild Ale".

Enough dodgy history! But I remember "Stitch" from my home-brewing youth being described as a "strong" (in alcohol) drink of the 17-18th Century. Except I now find it wasn't! The guys (and gals!) drank enormous amounts of beer/ale, and it was reckoned to provide half the calories of manual laborers of the day (farm workers ... and soldiers!). And "Ale" was reputed to be sweet. So, I elected to mash very high, beyond 69°C, to ensure I got what I was after. But I got a bit more than I planned!

But the things to note: 69°C isn't the limit for mashing, the B-Amylase can keep going for quite a while before succumbing to the heat (A-amylase is perfectly happy, 71-72°C it considers "optimum"). I just needed to be more careful about the quantity of B-amylase I had. I could have used "DP" (Diastatic Power) to provide a hint, but you must be very careful about "DP": I've found many of the published figures to be fanciful and malts from different areas vary hugely (premium UK MO pale malt has a DP only a fraction of US naff six-row stuff) and DP is only a measure of "reducing sugars" created, which reflects on B-amylase; A-amylase produces little reducing sugar ... DP is NOT a measure of total enzyme activity! The ability of yeast to ferment the most common "dextrin" (malt-triose) is quite variable - the WY-1099 I use isn't bad (doesn't seem to touch it) but another "dextrin-averse" strain I've used ("Windsor Ale") will begin to patiently chomp through it.

My "Stitch" mashed to SG1.071 (before diluted by the yeast starter). It has fermented out to about 5% ABV. IBU10.5! It's been a very useful exercise in hitting FG numbers that I have previously considered implausible. A Scottish Younger's 1879 "No.1" anyone? (OG1.098, apparent attenuation 59%, FG1.040!).

 

[peebee]

By-the-way ...

If anyone mentions "Colonial Williamsburg (American) beers, bottled Old Stitch", I won't be nice! (Bunch of charlatans). I can do far more research (on the Internet from my spare bedroom) than "Colonial Williamsburg" has put into their gawd awful mock up.

 

[Stan's Brew]

Were the farm workers really drinking 5% beer all day long! It's fascinating history, I am aiming to brew day long 'hiking beer' rather than drinking soft drinks or water on a day long hike in the hills, so far it's been an ordinary bitter to around 3.6% and I'm trying to go lower ABV and dry, a sweet 5% on a hike made from brown malt could be interesting. Will have to try to brew something with brown malt one day, does Stitch taste sweet?

 

[peebee]

Were the farm workers really drinking 5% beer all day long! ...

Who knows? Three hundred years on it is circumstantial evidence. "Stitch" has a reputation that's travelled through the centuries of being a head-banger. It was an Ale (not a beer), it was late enough to fall in with the trend to use new-fangled hops and not "Gruit", manual workers (and soldiers) did receive an allowance of ale or beer, not to get drunk (!) but to sate thirst and (increasingly thought of) fuel high physical demands. The latter suggests it was poorly attenuated and conserved much of its carbohydrate load (which wouldn't be intensely sweet if predominantly dextrin and "oligosaccharides".

A great subject for a bit of "experimental archeology", the sort you get to drink too! Though my first attempt at "Stitch" will be a good few days before it is "ready", and all the indications are that I won't much like it!

If you want to brew with "brown malt" you'll have to make it yourself (some enthusiasts do!) or go my route and "emulate" it (my formulas are about this forum somewhere): "Modern" brown malt has no resemblance. My formulas are for diastatic malts, and I do need to expand them a bit to cover the darker, stronger flavoured and non-diastatic stuff in use during the 19th C. and early 20th C.