Mashing in the 1970s

In the first half of the 20th century, UK brewers often still had relatively complicated mashing schemes. Ones with multiple steps. Was that still the case? Let’s have a look.

From the middle of the 19th century, the classic method in London is what I call “underlet mashing”. Which is effectively a step mash.

After an initial infusion mash and short rest, a smaller quantity of hotter water was added via the underlet, that is an inlet at the bottom of the tun. The internal rakes were then spun a few times to mix this water through the bed, raising the temperature by a few degrees. This method only worked if there were internal rakes in the mash tun.

Here’s a fairly typical example form Whitbread.

1971 Whitbread Trophy and Tankard mashing scheme
action	barrels	strike heat	time mashed	time stood	tap heat	gravity
mash	130	155º F	10	30
underlet	19	180º F		60	146º F	1053
sparge 1	182	165º F
sparge 2	75	160º F			155º F	1023
Source:
Whitbread brewing record held at the London Metropolitan Archives, document number LMA/4453/D/09/141.

Just to prove that this was a common method, even amongst the big brewers, here’s another example from a Big Six brewery.

1971 Watney Red Barrel mashing Scheme
action	barrels water per quarter	strike heat	stand
Mash	2	158º F	90
Underlet	0.1	190º F
Sparge 1	0.5	175º F
Sparge 2	3.5	160º F
total water	6
Source:
Watney Mann Quality Control Manual, page R.B. 1.

Though there is a note in the document saying that the underlet should only be performed if the initial temperature was too low.

In Scotland, where sparging was first developed, schemes had been pretty simple for more than a century. Just an infusion mash followed by a couple of sparges. It was also a scheme adopted by some regional English brewers.

For example, Boddington in Manchester.

1971 Boddington Bitter mashing scheme
action	strike heat	initial heat	time stood	tap heat
mash	150º F	142º F	75	140º F
sparge 1	162º F
sparge 2	158º F			151º F
Source:
Boddington brewing record held at Manchester Central Library, document number M693/405/134.

The temperatures are a fair bit lower than at Whitbread. Which would make sense, as given the very high rates of attenuation at Boddington – over 90% for their draught beers – low mashing temperatures would make sense.