Friday, 14 April 2023

Tetley cask Mild specifications (part five)

Just for a little variation, we're back with Tetley's beer specifications from 1982. Looking at the processes between the end of the boil and the start of fermentation.

Kicking off with the hop sparge. Which is, I suppose, intended to wash any wort that has been soaked up by the hops. For some reason the process isn't exactly the same as for the Bitter. Ever so slightly. Only 80 barrels go to the DeMarkus opposed to 85 barrels for Bitter.

10. HOP SEPARATION (SPARGE)
Whirlpool (Hop Back) 60 brls.
DeMarkus 80 brls.
Source:
Tetley Beer and Malt Specifications, 1985, beer page 9.

Next we have the water added before fermentation. For Bitter, only 100 barrels were added to the fermenter before the wort. For Mild, a lot more water was added: 150 barrels before the wort and 175 barrels after. I can understand adding more water to a weaker beer, but why in two lots?

11. BREAKDOWN WATER
a) Added to wort To FV prior to wort: 150 brls.
To FV after wort: 175 brls.
b) All water sterilised by steam in heat exchanger and cooled by Brewing/Chilled water. 30 secs, at 195 - 205°F.
Source:
Tetley Beer and Malt Specifications, 1985, beer page 9.

The same two-strain yeast was used. But a bit less of it than in the Bitter: 0.5 lbs per barrel rather than 0.625 lbs. Not sure why less yeast was needed. Because of the lower gravity? Maybe.

12. ADDITIONS BEFORE COLLECTION
a) Yeast - AB7/AB9 0.5 Ibs/brl. pressed yeast injected into wort main 30 mins, after start of 1st length.
b) Aeration Compressed air after cooling stage in Paraflow to give D.O. of 6 - 8 ppm.
c) Zinc as ZnS04 0.10 mg/1 into FV prior water
Source:
Tetley Beer and Malt Specifications, 1985, beer page 9.

The collection gravity is, unsurprisingly, about the same as the target OG of 1032º.  

13. COLLECTION
a) Temperature (°F) (°C) 63/64 (17.2)
b) Gravity 1031.8
(Metric) 1031.5
Source:
Tetley Beer and Malt Specifications, 1985, beer page 9.

There will be more of this. When I can be arsed. Or run out of other stuff. Or I'm off travelling again.

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