peebee
Out of Control
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!).
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!).
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