During both wars the government struggled to keep coal output at a sufficient level to meet demand. As things like kettles were generally powered by coal, a shortage of it caused acute difficulties. Even more so in breweries where everything was steam powered.
"The shortage of coal created further difficulties which were often aggravated by its poor quality. This need to conserve coal raised the question of copper boiling, and brewers found they had to reduce their boiling period almost to the limit of safety. It was also often difficult, with the low-quality of coal available in some districts, to maintain a sufficient head of steam on the boilers to obtain a suitable boiling temperature. When the coal situation became difficult brewers were asked to take the necessary steps to conserve fuel as much as possible. The experience of the last war, however, had taught them a lot about the saving of fuel, and its rising price in the intervening years had encouraged efficiency in this direction, so that there were not many improvements that could be carried out. Notwithstanding this they were subjected to frequent visits from inspectors and advisers from the Ministry of Fuel, many of whom knew little more than the theory of fuel consumption."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, pages 124 - 125.
Brewers in WW I had voluntarily reduced their coal consumption. So I can believe that most of the easy ways of cutting coal consumption had already been implemented.
Did brewers reduce boil times during the war? Whitbread certainly did, as these table show:
| Whitbread Ales in 1938 | |||||||||||
| Date | Year | Beer | Style | OG | FG | ABV | App. Atten-uation | lbs hops/ qtr | hops lb/brl | boil time (hours) | boil time (hours) |
| 23rd Feb | 1938 | 33 | Strong Ale | 1061.6 | 1016.5 | 5.97 | 73.21% | 8.47 | 2.23 | 1.25 | 1 |
| 25th Feb | 1938 | 33 | Strong Ale | 1059.0 | 1016.5 | 5.62 | 72.03% | 8.47 | 2.18 | 1.75 | 1.5 |
| 2nd Mar | 1938 | DB | Brown Ale | 1054.6 | 1016.0 | 5.11 | 70.70% | 9.98 | 2.36 | 1.25 | 1.25 |
| 22nd Feb | 1938 | Ex PA | Pale Ale | 1048.1 | 1012.0 | 4.78 | 75.05% | 7.49 | 1.54 | 1.33 | 1.42 |
| 1st Mar | 1938 | Ex PA | Pale Ale | 1048.3 | 1013.5 | 4.60 | 72.05% | 7.49 | 1.54 | 1.67 | 1.42 |
| 21st Feb | 1938 | IPA | IPA | 1036.5 | 1006.5 | 3.97 | 82.19% | 10.00 | 1.54 | 1.5 | 1.5 |
| 24th Feb | 1938 | IPA | IPA | 1037.1 | 1007.0 | 3.98 | 81.13% | 10.00 | 1.58 | 1.5 | 1.5 |
| 21st Feb | 1938 | LA | Mild | 1028.3 | 1008.0 | 2.69 | 71.73% | 7.44 | 0.90 | 1.25 | 1.33 |
| 22nd Feb | 1938 | PA | Pale Ale | 1048.3 | 1012.0 | 4.80 | 75.16% | 7.49 | 1.55 | 1.33 | 1.42 |
| 25th Feb | 1938 | PA | Pale Ale | 1048.6 | 1011.0 | 4.97 | 77.37% | 7.49 | 1.55 | 1.33 | 1.5 |
| 1st Mar | 1938 | PA | Pale Ale | 1047.8 | 1011.5 | 4.80 | 75.94% | 7.49 | 1.52 | 1.67 | 1.42 |
| 21st Feb | 1938 | X | Mild | 1035.7 | 1010.0 | 3.40 | 71.99% | 7.44 | 1.14 | 1.25 | 1.33 |
| 22nd Feb | 1938 | X | Mild | 1036.1 | 1011.0 | 3.32 | 69.53% | 7.87 | 1.23 | 1.25 | 1.08 |
| 25th Feb | 1938 | X | Mild | 1035.3 | 1010.0 | 3.35 | 71.67% | 7.44 | 1.11 | 1.25 | 1.25 |
| Average | 8.18 | 1.57 | 1.40 | 1.35 | |||||||
| Source: | |||||||||||
| Whitbread brewing record held at the London Metropolitan Archives, document number LMA/4453/D/01/105. | |||||||||||
| Whitbread Ales in 1945 | |||||||||||
| Date | Year | Beer | Style | OG | FG | ABV | App. Atten-uation | lbs hops/ qtr | hops lb/brl | boil time (hours) | boil time (hours) |
| 24th Aug | 1945 | DB | Brown Ale | 1043.3 | 1008.0 | 4.67 | 81.52% | 6.25 | 1.16 | 1 | 0.75 |
| 27th Aug | 1945 | IPA | IPA | 1031.6 | 1006.0 | 3.39 | 81.01% | 8.22 | 1.13 | 1.25 | 1.25 |
| 4th Apr | 1945 | PA | Pale Ale | 1039.4 | 1010.0 | 3.89 | 74.62% | 6.03 | 1.01 | 1.08 | 1 |
| 24th Aug | 1945 | PA | Pale Ale | 1039.5 | 1012.5 | 3.57 | 68.35% | 5.85 | 1.01 | 1.08 | 0.75 |
| 4th Apr | 1945 | XX | Mild | 1028.2 | 1009.0 | 2.54 | 68.09% | 5.63 | 0.70 | 1 | 0.75 |
| 5th Apr | 1945 | XX | Mild | 1028.4 | 1008.5 | 2.63 | 70.07% | 5.67 | 0.71 | 1 | 0.75 |
| 24th Aug | 1945 | XX | Mild | 1028.1 | 1010.0 | 2.39 | 64.41% | 5.67 | 0.71 | 1 | 0.75 |
| 8th June | 1945 | XXXX | Strong Ale | 1043.4 | 1014.0 | 3.89 | 67.74% | 6.44 | 1.19 | 1 | 1 |
| 2nd Oct | 1945 | IPA | IPA | 1031.6 | 1006.0 | 3.39 | 81.01% | 8.53 | 1.22 | 1.25 | 1.5 |
| 3rd Oct | 1945 | XX | Mild | 1028.4 | 1010.0 | 2.43 | 64.79% | 5.77 | 0.72 | 1 | 0.75 |
| 3rd Oct | 1945 | PA | Pale Ale | 1038.8 | 1011.5 | 3.61 | 70.36% | 5.85 | 1.03 | 1.08 | 0.75 |
| 5th Oct | 1945 | DB | Brown Ale | 1043.6 | 1011.0 | 4.31 | 74.77% | 6.25 | 1.18 | 1 | 1.25 |
| 19th Oct | 1945 | XX | Mild | 1028.2 | 1008.5 | 2.61 | 69.86% | 5.77 | 0.72 | 1 | 1.33 |
| 31st Dec | 1945 | XX | Mild | 1027.8 | 1009.0 | 2.49 | 67.63% | 5.77 | 0.68 | 1 | 1 |
| Average | 6.27 | 0.94 | 1.05 | 0.97 | |||||||
| Source: | |||||||||||
| Whitbread brewing records held at the London Metropolitan Archives, document numbers LMA/4453/D/01/112 and LMA/4453/D/01/113. | |||||||||||
For the first copper, the average boil time fell from 84 minutes to 63 minutes and for the second copper from 81 to 58 minutes. Whereas before WW I, the shortest boil at Whitbread was 90 minutes.
The reduction was even larger at Barclay Perkins:
| Barclay Perkins Ales in 1939 | |||||||||||||
| Date | Year | Beer | Style | OG | FG | ABV | App. Atten-uation | lbs hops/ qtr | hops lb/brl | boil time (hours) | boil time (hours) | boil time (hours) | boil time (hours) |
| 19th Jun | 1939 | A | Mild | 1030.8 | 1007.5 | 3.08 | 75.65% | 7.00 | 0.84 | 2.5 | 2.25 | 2 | 2 |
| 19th Jun | 1939 | X | Mild | 1034.8 | 1010.0 | 3.28 | 71.26% | 7.00 | 0.95 | 2.5 | 2.25 | 2 | 2 |
| 19th Jun | 1939 | XX | Mild | 1042.7 | 1015.0 | 3.66 | 64.87% | 7.00 | 1.14 | 2.5 | 2.25 | 2 | 2 |
| 20th Jun | 1939 | PA | Pale Ale | 1052.5 | 1014.5 | 5.03 | 72.38% | 7.50 | 1.54 | 2.5 | 2.75 | 2 | |
| 20th Jun | 1939 | XLK (trade) | Pale Ale | 1045.7 | 1017.0 | 3.80 | 62.80% | 7.50 | 1.37 | 2.5 | 2.75 | 2 | |
| 20th Jun | 1939 | XLK (bottling) | Pale Ale | 1035.8 | 1011.5 | 3.21 | 67.88% | 7.50 | 1.15 | 2.5 | 2.75 | 2 | |
| 21st Jun | 1939 | XX | Mild | 1042.7 | 1011.5 | 4.13 | 73.08% | 7.00 | 1.18 | 2.5 | 2.25 | 2 | |
| 21st Jun | 1939 | X | Mild | 1034.8 | 1010.5 | 3.22 | 69.86% | 7.00 | 0.96 | 2.5 | 2.25 | 2 | |
| 22nd Jun | 1939 | PA | Pale Ale | 1052.8 | 1018.5 | 4.54 | 64.96% | 7.50 | 1.54 | 2.5 | 2.25 | 2 | 2 |
| 22nd Jun | 1939 | XLK (trade) | Pale Ale | 1045.8 | 1014.5 | 4.14 | 68.35% | 7.50 | 1.35 | 2.5 | 2.25 | 2 | 2 |
| 22nd Jun | 1939 | IPA (bottling) | IPA | 1043.9 | 1013.5 | 4.03 | 69.27% | 7.50 | 1.28 | 2.5 | 2.25 | 2 | 2 |
| 29th Jun | 1939 | XLK (trade) | Pale Ale | 1045.7 | 1014.5 | 4.12 | 68.26% | 7.50 | 1.38 | 2.5 | 2.25 | ||
| 29th Jun | 1939 | IPA (bottling) | IPA | 1043.8 | 1012.5 | 4.14 | 71.48% | 7.50 | 1.32 | 2.5 | 2.25 | ||
| Average | 7.31 | 1.23 | 2.5 | 2.37 | 2 | 2 | |||||||
| Source: | |||||||||||||
| Barclay Perkins brewing record held at the London Metropolitan Archives, document number ACC/2305/01/623. | |||||||||||||
| Barclay Perkins Ales in 1945-46 | |||||||||||
| Date | Year | Beer | Style | OG | FG | ABV | App. Atten-uation | lbs hops/ qtr | hops lb/brl | boil time (hours) | boil time (hours) |
| 7th Apr | 1945 | XLK | Pale Ale | 1035.4 | 1012.8 | 3.00 | 63.98% | 5.09 | 0.75 | 1.5 | 1.5 |
| 22nd Feb | 1945 | XX | Mild | 1031.4 | 1009.5 | 2.90 | 69.75% | 5.49 | 0.71 | 1.5 | 1.5 |
| 22nd Feb | 1945 | X | Mild | 1029.7 | 1008.5 | 2.80 | 71.38% | 5.49 | 0.65 | 1.5 | 1.5 |
| 13th Jul | 1945 | XX | Mild | 1031.4 | 1010.0 | 2.83 | 68.15% | 4.96 | 0.67 | 1.5 | 1.5 |
| 25th Jan | 1946 | XLK | Pale Ale | 1035.3 | 1010.0 | 3.35 | 71.67% | 7.00 | 1.04 | 1.5 | 1.5 |
| 25th Jan | 1946 | IPA | IPA | 1031.5 | 1009.0 | 2.98 | 71.43% | 7.00 | 0.93 | 1.5 | 1.5 |
| Average | 5.84 | 0.79 | 1.5 | 1.5 | |||||||
| Source: | |||||||||||
| Barclay Perkins brewing record held at the London Metropolitan Archives, document number ACC/2305/01/626. | |||||||||||
The first copper fell from 150 to 90 minutes, the second copper from 145 to 90 minutes. And while there had been up to four coppers pre-war, by 1945 there were never more than two.
The two sets of tables also show the fall in hopping rates. At Whitbread, the average hopping rate per quarter fell from 8.18 lbs to 6.27 lbs. Or 23%. At Barclay Perkins from 7.31 lbs to 5.84 lbs. Which is s lightly smaller percentage fall: 20%
Now some research done into boiling:
"Investigations which were carried out in the method of operating the small scale brewing plant at Birmingham University for the purpose of carrying out brewing trials with the new varieties of hops grown at East Malling Research Station brought to light some interesting facts with regard to flavours transmitted to beer under different boiling conditions. It was found that the temperature at which the copper boils is an important factor, and that if the temperature which corresponds to that obtained in an open brewing copper is not exceeded, the characteristic flavour which would be expected to be obtained from a physical examination of the hops can be readily detected in the beer. When this temperature is exceeded, however, as it would be for instance if a pressure copper was used, this characteristic flavour disappeared and a dead level of flavour is obtained, no matter what hops are used."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 125.
That's quite an odd claim: that you got no hop flavour if you boiled at a higher temperature than an open copper. You may remember that different types of brewers used different designs of copper. In London, where Porter brewers wanted to build colour, sealed, domed coppers were used. While Burton Pale Ale brewers - who wanted to keep their beer as pale as possible - used open coppers.
Next time it's isinglass.
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