Thursday, 30 October 2014

German brewing in 1966 - malting

Now we've got barley out of the way we can turn to the business of turning it into malt.

First some general stuff:

"Many German breweries, particularly in the south, have their own maltings. The increasing demand is being filled by existing commercial maltings.

The five-day week has forced maltings to adjust to a 7-day germination period, and malting methods must be adjusted accordingly. A germination period of 8-9 days was normal some years ago and for dark malts it was even longer. However, as a day was usually lost after casting the steep before the barley began to grow, we really only had a 7-day germination period in an 8-day malting period."
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 15.

Narziss keeps moaning about the trouble the introduction of a 5-day, 40-hour working week. As if it were the work of the devil.

I think it's much rarer now for German breweries to have their own maltings, as in the UK. Come to think of it, about the only place I can think of where this does still happen is the Czech Republic. In the 19th century all the famous Burton and Edinburgh brewers had their own maltings. This was understandable as they specialised in Pale Ales, beers where the quality and colour off the malt was paramount. But gradually they moved over to buying in all their malt during the first half of the 20th century. Presumably because it was of reliable quality.

Now steeping:

"Steeping.—As a result of a fundamental change in the concept of steeping, we have achieved a position whereby a well-modified, completely satisfactory malt can be produced in a 7-day germination period. A shorter steeping period is now possible by making use of methods such as warm-water steeping (14-18° C), frequent dry steeping, periodic removal of CO2 by suction, sprinkling of the steeped barley, and re-circulation of the barley two or three times during the steeping period. By means of these methods less damage is done to the barley and the steep is cast with the barley visibly germinating and even at times showing two or three rootlets. This results in increased utilization of the germination plant. With warm-water steeping, it is essential to main tain an even temperature throughout; the steep room has to be controlled accordingly and, when using higher temperatures, a punctual CO2 removal must be carried out, preferably controlled by a clock. If cold air is sucked into the steep this will result in delayed water absorption and uneven germination."
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 15.

Steeping was a huge deal in Britain when malt was taxed. Because it was taxed on the volume when it came out of steeping. As this could be manipulated through the moisture content, there were strict rules about what, and for how long, maltsters were allowed to do.

I haven't the foggiest idea of steeping temperatures, so I looked it up in a modern British brewing manual. Here's what it says:

"The steep-water temperature should be controlled. At elevated temperatures water uptake is faster but microbial growth is accelerated and the grain may be damaged or killed. The best temperature for steeping immature (partly dormant) grain is low (about 12 ºC, 53.6 ºF). For less dormant grain a value of 16-18 ºC (60.8-64.4 ºF) is often used."
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, pages 14 - 15.

That seems pretty much in line with what Narziss derscribes. Briggs also describes CO2 extraction:

"Air rests are used between steeps. After a steep has been drained air, which should be humid and at the correct temperature, is sucked down through the grain. Such downward ventilation, or `CO2 extraction', assists drainage, provides the grain with oxygen, removes the growth-inhibiting carbon dioxide and removes some of the heat generated by the metabolizing grain. In consequence, and in contrast to traditional practice, barley leaving the steep has usually started to germinate."
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, page 15.

Now something about moisture content:

"A number of investigations have shown that a sufficient moisture content of the barley is absolutely essential. It is possible to reduce germination time even when a very high degree of steeping is used, provided steps are taken to avoid subsequent drying out of the barley. Formerly moisture contents of 45-46% were used only when steeping dark malts but now this level of moisture is not unusual even for pale malts. By improving the degree of steeping on the 1964 season barleys (which were of low extract and enzymically poor) results shown in Table I could be obtained."
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, pages 15 - 16.

Why would you have a greater moisture content in dark malts?

Here's that table.

TABLE I
Effect of Steeping on Analysis

Degree of steeping

43% 46%
Moisture content 4.60% 4.80%
Extract (dry) 80.10% 80.80%
Coarse/fine grind difference 2.70% 1.70%
Protein content 11.90% 11.70%
Degree of protein modification 33.80% 35.40%
Colour (E.B.C.) 2.2 2
Conversion (min.) 10.15 10.15
Malting loss 9.50% 12.70%
Germination loss 4.70% 4.10%
Steeping time (hr.) 62 74

Want to know how British malt compares? Briggs reckons the dry extract of pale malt is 77-83%*. The German malt is smack in the middle of that range. For darker British malts the extract was lower, 75-78%**. Briggs states that malting losses account to 6.5% - 14%, but breaks them down differently to Narziss:

"Malting losses can be defined in several ways. If they are defined in terms of the losses in dry weight, which occur when cleaned barley entering the steep is recovered as kilned malt and has been de-culmed (dressed), then the losses sustained in making conventional malts are usually in the ranges: steeping losses, 0.5 - 1.5%; germination losses, 3.5 - 7.5%; rootlets, 2.5 - 5.0%. These divisions are artificial, since some respiration and growth occur in the steeping phase and in the initial stages of kilning."
"Brewing: science and practice", by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, 2004, page 17.

That leaves the German losses right at the top end, or a little beyond, of the British range.

More about malting and malts next time.

Wednesday, 29 October 2014

Brewing in WW II (part seven)

We're back in the middle of a WW II hop field.

And in the middle of the war. I wonder how thins are going?

"The 1942 crop was of uniform good quality and was considered to be the best for 10 years. The quantity picked, however, was still short of brewers' requirements, and they were only able to obtain 80 per cent, of what they had asked for. A new disease of the hop plant, which had made its appearance a few years previously in the Kent hop gardens, had become virulent that year. It was the virus disease, Verticillium Wilt, which attacked the plant, causing it to wither away, and was having an adverse influence on the yield in some gardens. Although investigations were then extensively being carried out at East Mailing into its cause, the only method of combating it was by grubbing. The hop crop in 1943 was of fair average quality, although it tailed off towards the end of the picking. The yield was higher than in the previous two years, although it was barely sufficient to supply the brewers' requirements. The yield: of the 1944 crop was again short, and brewers had to be content with a 20 per cent, reduction in their allocations, while the quality was rather below the average."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 123.

A new hop disease is the last thing anyone needed. Especially if the only cure was grubbing up the bines.


Why don't we take a look at hop usage during the war?

Hop usage in WW II
year hops prep-arations of hops hop substitutes bulk barrels qtrs. malt lbs hops per qtr lbs hops per barrel
1938 277,846 145 29 24,339,360 4,307,776 7.22 1.28
1939 285,715 113 13 25,691,217 4,536,400 7.05 1.25
1940 265,512 132 108 24,925,704 4,176,167 7.12 1.19
1941 251,354 186 166 28,170,582 4,447,843 6.33 1.00
1942 223,007 246 71 29,584,656 4,490,029 5.56 0.84
1943 231,589 250 96 29,811,321 4,555,652 5.69 0.87
1944 243,900 277 137 31,380,684 4,731,148 5.77 0.87
1945 244,822 714 139 31,990,334 4,896,364 5.60 0.86
1946 226,197 1,414 168 31,066,950 4,644,176 5.46 0.82
1947 217,759 1,423 191 30,103,180 4,187,780 5.82 0.81
Source:
Brewers' Almanack 1955, page 62.

Hopping rates did indeed fall. By 1945, the average amount of hops per barrel was 33% lower than in the last full year of peace, 1938. In terms of hops per quarter of malt, it was 22.5% lower. The latter figure is important as it takes beer gravity out of the equation.

"Before the war most brewers endeavoured to hold about 6 months' stock of hops above their year's requirements, but the disaster of 1940 practically wiped this out, and the principal difficulty ever since has been to maintain a sufficiently high hop rate with the reduced quantity of hops available, especially in those years when the quantity and quality was low. The agreed average price for the hops of the 1944 crop was £20 per cwt, a little more than double the price at the beginning of the war."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 123.

Here are the production and prices of hops during the war:

Hop production, imports and exports 1938 - 1947
Year ended 31st Dec. Acreage Estimated Produce Yield per acre Average Price of English Hops per Season, Sept. to Dec. Imports: Less Re-Exports Exports: British Hops Consumption Years ended 30th Sept. following shortfall / surplus
Cwts. Cwts. £ s. d. Cwts. Cwts. Cwts. Cwts.
1938 18,460 257,000 13.9 9 0 0 45,287 12,580 286,716 2,991
1939 18,812 288,000 15.3 9 10 0 7,840 16,050 265,512 14,278
1940 18,592 270,500 14.5 12 0 0 14,675 26,830 251,354 6,991
1941 18,158 262,800 14.5 15 0 0 31 17,209 223,007 22,615
1942 18,420 261,900 14.2 17 10 0 2,963 30,673 231,689 2,501
1943 19,131 285,200 14.9 18 0 0 198 24,941 243,900 16,557
1944 19,603 253,900 13 20 0 0 0 26,525 244,822 -17,447
1945 19,957 282,900 14.1 21 0 0 574 32,337 226,197 24,940
1946 21,163 257,451 13.4 22 10 0 29,243 35,056 217,759 33,879
1947 22,142 289,908 13.2 23 10 0 7,716 31,661 231,470 34,493
Source:
Brewers' Almanack 1955, page 63.

The price was indeed £20 per cwt. in 1944. You can see that the price of hops, in contrast to that of malt, rose every year of the war and continued to rise after its end. And you can see from the shortfall/surplus figure (production plus imports minus exports and usage) that there was no room to build stocks, with only tiny surplus or even, as in 1944, a deficit. It did indeed look serious in 1944. The shortfall wiped out the surplus of the previous two years.

Brewers must have been the only people disappointed by the USA's entry into the war:

"Naturally attempts were made to remedy the very serious position in 1941, but the entry of America into the war cut short any prospect of importing from that source, and Continental hops were out of the question. Lupulin, which was little more than kiln dust, was offered from America, but the quantity which reached this country was small, later quite a useful hop concentrate was imported from the United States, but the quantity available was limited. It had a preservative value equal to from five to seven times that of hops and was a slight help in improving the situation. It has a strong American flavour, however, and the proportion that could be used had in consequence to be limited."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 123.

Because it ended hopes of getting American hops. You can see from the first table that the quantity of preparations of hops - which is where I think Lupulin belongs - was indeed tiny.

Picking hops wea still causing problems, too:

"The difficulties the growers had experienced in getting their whole crop picked and the delay that often occurred before it could all be obtained before it was over ripe and turned brown, again brought the question of picking machines into prominence. Some of the growers have been experimenting with these machines and necessary improvements have been made so that with the prospective increased costs of labour in the future it is likely that picking machines will be used in larger numbers."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 123.
There was also something I skipped about the introduction of combine harvesters during the war because of labour shortages. Their use was one reason much of the wartime crops were damaged after harvesting. It seems the war gave the mechanisatoin of agriculture a big push.

It seems supply problems continued after thge war:

"The present position with regard to the supply of hops at the end of 6 years is causing considerable anxiety as stocks held at the outbreak of war disappeared after the destruction of so large a proportion of the 1940 crop, and although hop rates have been reduced to the lowest possible limit, not sufficient hops are now being grown to meet brewers' requirements, and the amount available this year represents a shortage of from 6 to 8 weeks in a full year, which will become more serious next year. Although the Ministry of Agriculture has given permission to plant up a further 2,500 acres of hops it has been impossible to convince the Hops Marketing Board of the seriousness of the position and of the certainty that a much larger quantity than is at present being grown would be readily absorbed, even should there be a drop in the output of beer in the near future. Unless something can be done to obtain alternative supplies, therefore, the serious prospect of restricting the output of beer may become a reality."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 123.

If you look at the table above you can see that it isn't true that insufficient hops were being grown to meet demand. Even after exporting 30,000 cwt there was still a surplus. Not a huge one, but it was there. Beer output did indeed fall after war's end. It didn't start increasing until 1959 and didn't get back to the 1945 level until the end of the 1960's*.

Next time we'll be looking at brewing itself.




* 1971 Brewers'Almanack, page 54

Tuesday, 28 October 2014

German Helles in 2014

Right, time to start making some use of all this information I've been wasting my evenings collecting. My only accompaniment the quiet sobbing of my negected wife and kids.

I suppose I should make this clear at the start. What I mean by Helles, isn't any old sort of pale Lager that isn't Pils. I should really use the full name of the style I'm discussing today: Helles Lagerbier or Lagerbier Hell. I'm using the shorthand of Helles because I can't be arsed to go and change the style on hundreds of table entries.

It's a very popular style amongst the breweries I'm looking at. No surprise, as most are from Bavaria. Where Helles is the most popular style. There were only more examples in my set of two styles: Pils and Hefeweizen. Those are, unsurprisingly, the three most popular styles in Germany.

Oh, I suppose I should tell you how I split apart Helles Lagerbier and Helles Export. Some of the latter were identified by the brewery as Export. With others it wasn't clear what, if anything, the brewery considered their style. So I used something mentioned in the Deutscher Brauer-Bund website style descriptions: that Export has a minimum gravity of 12 Platoº.

It seems like a good enough dividing line, so that's what I've used. Though it is pretty arbitrary. I'll classify a beer of 11.9º Helles and one of 12º Export. You have to draw the line somewhere, but I'm not claiming my classification is perfect.

I suppose I should show you the beers now:

German Helles in 2014
Brewer Town Beer OG FG OG Plato ABV App. Atten-uation bitterness (EBU)
Paulaner Munich Münchner Hell Leicht 1030.4 1005.8 7.7 3.20 80.93%
Göller Zeil am Main Hausbrauerbier 1044.9 1011.7 11.2 4.30 73.92%
Püls-bräu Stadtsteinach Weismainer Urhell 1046.1 1010.8 11.5 4.60 76.69%
Bürgerbräu Hersbruck Hersbruck Lagerbier 1045.3 1009.9 11.3 4.60 78.13%
Ammerndorfer Bier Dorn Bräu Ammerndorf Hell 1045.7 1010.3 11.4 4.60 77.46%
Privatbrauerei Kesselring Marktsteft Hell 1046.1 1010.0 11.5 4.70 78.31%
Zum Löwenbräu Flair Hotel Adelsdorf Vollbier Hell 1047.4 1011.2 11.8 4.70 76.36%
Brauerei Windsheimer Gutenstetten Vollbier 1047.8 1011.6 11.9 4.70 75.73%
Forschungsbrauerei Munich Münchener Vollbier Hell 1044.0 1007.9 11 4.70 82.05%
Arnsteiner Brauerei Seinsheim Ernte Hell 1044.4 1007.6 11.1 4.80 82.90%
Brauerei Gasthof Wiethaler Lauf an der Pegnitz Lagerbier Hell 4.80
Brauereigasthof Winkler Berching  Lagerbier Hell 1045.7 1008.8 11.4 4.80 80.74%
Klosterbrauerei Andechs Andechs Vollbier Hell 1046.1 1009.2 11.5 4.80 80.05%
Braugold Erfurt Braugold Hell 1046.1 1009.2 11.5 4.80 80.05%
Holsten Hamburg Altona Edel 1044.9 1007.3 11.2 4.90 83.73% 23
Kulmbacher Brauerei Kulmbach Kulmbacher Feinmild 1045.3 1007.7 11.3 4.90 82.99%
Kulmbacher Brauerei Kulmbach Mönchshof Bayerisch Hell 1045.3 1007.7 11.3 4.90 82.99%
Kulmbacher Brauerei Kulmbach EKU Hell 1045.7 1008.1 11.4 4.90 82.27%
Brauhaus Leikeim Altenkunstadt Hell 1045.7 1008.1 11.4 4.90 82.27%
Paulaner Munich Münchner Hell 1046.1 1008.5 11.5 4.90 81.57%
Kulmbacher Brauerei Kulmbach Kulmbacher Lager Hell  1046.1 1008.5 11.5 4.90 81.57%
Kulmbacher Brauerei Kulmbach Mönchshof Lager 1046.1 1008.5 11.5 4.90 81.57%
Gasthof Gundel Kammerstein Urhell 1046.1 1008.5 11.5 4.90 81.57%
Brauerei Weller  Erlangen 3x11 1044.0 1006.5 11 4.90 85.35%
Kitzmann-Bräu Erlangen Helles 1046.5 1008.9 11.6 4.90 80.87%
Kitzmann-Bräu Erlangen Kitzzz 1046.5 1008.9 11.6 4.90 80.87%
Brauerei Hermann Sigwart Weißenburg Hell 1046.5 1008.9 11.6 4.90 80.87%
Schübel Bräu Stadtsteinach a fränkisch 1047.4 1009.7 11.8 4.90 79.52%
Strauß Karl Brauerei Treuchtlingen Wettelsheimer Helles 1047.4 1009.7 11.8 4.90 79.52%
Göller Zeil am Main Hell 1047.4 1009.0 11.8 5.00 81.00%
Hacker-Pschorr Munich Münchner Hell 1046.1 1007.8 11.5 5.00 83.19%
Schwechater Vienna Schwechater Bier 1046.1 1007.8 11.5 5.00 83.19%
Kulmbacher Brauerei Kulmbach Original 1046.5 1007.5 11.6 5.10 83.99% 21
Weihenstephan Freising Original 1046.5 1007.4 11.6 5.10 84.10% 21
Spaten Munich Münchner Hell 1047.0 1007.1 11.7 5.20 84.88%
Löwenbräu  Munich Original 1047.4 1007.5 11.8 5.20 84.17%
Average 1045.6 1008.7 11.4 4.8 81.01% 21.7
Sources:
Brewery websites.

As you can see, there's not a huge amount of variation. And the average does look like the spec of a tyopical Helles: 11.5º Plato, 4.8% ABV, 80% apparent attenuation. The biggest varition is in the degree of attenuation, which ranges from 74% to 85%.

Though by limiting the gravity to 11.9 º Plato, I did, of course, dictate that the beers would be generally similar.

Pils next time.

Monday, 27 October 2014

Saturday 1st November

Or coming Saturday.

Just discovered that there is a rail service of some sort out in the sticks of New Jersey where I'll be this week. Which means I'll be able to get to NYC on Saturday.

If anyone fancies meeeting up for a beer, I'll be in Blind Tiger about 13:00. I'll probably wander off later to DBA, Jimmy's No. 43 and Hop Devil.

Brewing in WW II (part six)

We're now moving on to hops.

Starting with the position at the outbreak of war.

"When war broke out the position with regard to hops was not a very favourable one for brewers, as owing to the policy adopted by the Hops Marketing Board in restricting production, there was little surplus in any year, and the reserves in the brewers' hands were small. It was perhaps fortunate that the 1939 crop, although not pretty to look at, was the ripest for many years and was large, and in excess of requirements. The average price for Fuggles that year was £9 5s. and for Goldings £11 15s."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 122.

The Hops Marketing Board was set up in response to a crisis in Britain's hop industry during WW I. The reduction in beer gravities meant that brewers needed far fewer hops. This in turn caused a glut of hops and many growers and dealers faced going out of business until the government stepped in and bought the crop. It seems efforts to control supply weren't quite so handy when another war broke out.

1940 was a very bad year for British hops:

"In the following year the Battle of Britain was taking place when the hops were ready to pick, and there was a great shortage of pickers owing to natural disinclination to go into such a dangerous area. The crop was again a large one-and the quality was high, but notwithstanding the efforts of the growers to get it all picked quite a large proportion of it had to be left to blow away. An attempt was made to weigh and value the hops on the farms that year, but as this decision was arrived at too late in the year to enable it to be carried out successfully, it was abandoned and all the hops were sent to the Borough. This delayed matters considerably, and although brewers were exhorted to remove their allocations to a safer place they were slow in carrying this out, and when the Borough was subjected to the disastrous air raid on 29th December, many of the destroyed warehouses were full of hops, and it was estimated that something like one-third of the total crop was lost, among which were most of the best Goldings."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 122.

First the harvest was disrupted by the Battle of Britain. In peacetime East End families migrated down to Kent in the late summer to harvest hops. No-one was going to take their kids somewhere there was battle going on, albeit in the air. Then, in one of the first big raids on London, Borough was badly hit and a significant percentage of that year's crop destroyed. Keeping so many hops in a vulnerable part of central London wasn't the greatest idea.

"This brought about a serious state of affairs, as very few brewers had more than a small reserve stock of hops to fall back upon, and some were reduced to a very low figure. Hop rates had therefore drastically to be cut, and in many cases lower hop rates were used then ever before in the history of brewing."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, pages 122 - 123.

Did they really cut hopping rates to unheard of lows? Why don't we take a look at what happened at Whitbread. I've deliberately picked their two most hop-oriented beers, Pale Ale and IPA.

Whitbread IPA 1938 - 1948
Year OG FG ABV App. Atten-uation lbs hops/ qtr hops lb/brl boil time (hours) boil time (hours) hops
1938 1037.1 1007.0 3.98 81.13% 10.00 1.58 1.5 1.5 MK and EK
1939 1037.1 1008.0 3.85 78.44% 10.00 1.51 1.5 1.75 MK, EK, Sussex and Worcester
1940 1037.2 1007.0 4.00 81.18% 10.38 1.53 1.5 1.92 MK and EK
1940 1036.3 1007.5 3.81 79.34% 9.73 1.45 1.5 1.67 MK and EK
1941 1034.3 1005.5 3.81 83.97% 8.57 1.21 1.5 1.75 MK and Worcester
1942 1031.5 1005.0 3.51 84.13% 8.44 1.08 1.25 1.5 MK and EK
1943 1031.3 1007.5 3.15 76.04% 8.53 1.11 1.25 1.33 EK and Worcester
1944 1030.9 1005.0 3.43 83.82% 8.53 1.12 1.25 1.75 MK
1945 1031.6 1006.0 3.39 81.01% 8.53 1.22 1.25 1.5 MK and KT
1946 1029.4 1005.5 3.16 81.29% 8.90 1.12 1.25 1.25 MK and Sussex. Hopulon.
1947 1033.2 1007.5 3.40 77.41% 9.42 1.29 1.25 1.25 MK, EK and Worcester. Hopulon.
1948 1032.2 1005.5 3.53 82.92% 9.00 1.18 1.25 1.33 MK and EK. Hopulon.
Sources:
Whitbread brewing records held at the London Metropolitan Archives, document numbers LMA/4453/D/01/105, LMA/4453/D/01/107, LMA/4453/D/01/108, LMA/4453/D/01/109, LMA/4453/D/01/110, LMA/4453/D/01/112, LMA/4453/D/01/113, LMA/4453/D/01/114 and LMA/4453/D/01/115.


Whitbread PA 1938 - 1948
Year OG FG ABV App. Atten-uation lbs hops/ qtr hops lb/brl boil time (hours) boil time (hours) hops
1938 1048.6 1011.0 4.97 77.37% 7.49 1.55 1.33 1.5 MK and EK
1939 1048.2 1012.0 4.79 75.10% 7.33 1.41 1.17 1.08 MK, EK, Sussex and Worcester
1940 1044.1 1013.5 4.05 69.39% 7.14 1.27 1.33 1 MK and EK
1941 1042.9 1015.0 3.69 65.03% 6.54 1.11 1.33 1 MK and EK
1941 1042.5 1011.5 4.10 72.94% 5.62 1.00 1.33 1 MK and Worcester
1942 1038.6 1010.5 3.72 72.80% 6.03 0.96 1.25 1.25 MK and EK
1943 1039.2 1010.5 3.80 73.21% 6.03 1.00 1.08 0.75 EK and Worcester
1944 1039.0 1010.5 3.77 73.08% 6.03 1.02 1.08 1.25 MK and EK
1945 1038.8 1011.5 3.61 70.36% 5.85 1.03 1.08 0.75 MK and KT
1946 1039.5 1012.0 3.64 69.62% 5.95 1.02 1.08 1.25 MK. Hopulon.
1946 1032.6 1008.0 3.25 75.46% 5.88 0.83 1.08 0.75 EK and MK. Hopulon.
1947 1034.2 1011.0 3.07 67.84% 6.30 0.95 1.08 1 MK and Worcester. Hopulon.
1948 1034.9 1010.0 3.29 71.35% 6.42 0.93 1.08 1.25 MK and EK Hopulon.
Sources:
Whitbread brewing records held at the London Metropolitan Archives, document numbers LMA/4453/D/01/105, LMA/4453/D/01/107, LMA/4453/D/01/108, LMA/4453/D/01/109, LMA/4453/D/01/110, LMA/4453/D/01/111, LMA/4453/D/01/112, LMA/4453/D/01/113, LMA/4453/D/01/114 and LMA/4453/D/01/115.

You can see that the hopping rate did fall in 1940 and 1941. PA dropped from 1.55 to 1 lbs per barrel, IPA 1.58 to 1.21 lbs per barrel. But as there were also reductions in gravity, you really need to look at the hops per quarter of malt. That’s a 36% drop for PA, 24% for IPA, if we're looking at the per barrel rate. Taking into account the gravity fall by using the per quarter figure shows smaller decreases, of 25% and 14%, respectively. That doesn't seem such a huge reduction as sugegsted in the article.

Note also the use of hopulon, some sort of hop preparation, after the end of the war. The problems with hop supply didn't end with hostilities.

It seems they'd learned the lesson of the 1940 bombing disaster:

"In 1941 the difficulties experienced in the previous year had brought about a reduction in the acreage of over 800, climatic conditions were unfavourable, and the crop was generally of poor quality. It was unfortunate that in view of the great shortage of hops the crop was small and brewers were only able to obtain 76 per cent, of their requirements. The scheme for sampling and weighing on the farms was put into operation that year, and the hops were sent direct to the brewers who were advised to distribute them as much as possible, which they were not slow to do. Picking did not present so many difficulties, as by that time the air-raids on London had become intense and people were only too glad of an opportunity for a respite."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 123.

I can see how Kentish hop fields would be a relief from nightly bombing. Once the Battle of Britain was over the Kent countryside was relatively peaceful.

More on hops next time.