Brewing in the 1950’s - Cold Storage of Hops

I was really pleased to find this in Jeffery. A neat little section on the storage of hops.

A couple of times during my last US tour this topic came up. When I was asked about the level of bitterness in the recipes in “The Home Brewer’s Guide to Vintage Beer”. “Weren’t hops less bitter in the past?” “Wouldn’t hops have quickly lost their bitterness through inadequate storage?”

In fact even in the 19th century, they stored hops very carefully and knew how to preserve their best properties. The method was still essentially the same in the 1950’s.

“Cold Storage of Hops. Before we conclude our article on hops we do feel it most necessary to include a few notes on the cold storage of hops. Although this process has been tested for many years and is found to give excellent results, we find that in some quarters mistaken ideas still exist as to its value. Our own experience justifies the saying that if properly carried out with the right kind of hop it is a process of the utmost value. In the first place, it is wrong to imagine that any old store so long as it is cold will do. It is essential that the cold store is carefully and effectively insulated, not only for the sake of maintaining a low temperature at a constant figure, but in order to prevent any ingress of warmer air. Warm air may bring with it moisture which may condense on the hops. There are two systems of cooling stores. One is by circulating air over cold pipes in a chamber outside the store, and then blowing it in by a fan through ports fixed at intervals in a duct. The other system is by brine pipes placed in the store itself through which brine is constantly being pumped. The first-named process has the disadvantage of causing a certain amount of draught and movement of the air. Unless the cold air is carefully introduced into the store, there is a danger of drying up the hops. The ports in the air duct must be so arranged that no air strikes direct on a pocket of hops. The air should impinge on a bare wall or passage, and then be diffused over the store. The introduction of air must never be carried out in violent gusts, but must take place steadily and regularly.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 186.

So there you have it: you need the right type of cold store. You don’t want warm air coming in and getting the hops wet. But you also didn’t want to dry the hops out by blowing too much cold air over them.  Who would have guessed that it was so complicated?

Here’s a description of the second, superior method of cooling the cold store:

“The alternative system of internal brine pipes is preferable. The moisture is extracted from the air in the store and is deposited on the surface of the pipes in the shape of frost or snow. It is essential to extract the moisture from the air, whichever process is adopted. With brine pipes there is very little movement of the air. However, there is a danger with brine pipes in the event of the circulation unavoidably stopping for any length of time. The frost on the pipes will melt, and cause a great deal of moisture. It is therefore necessary to provide drip troughs in order to catch the moisture. It must on no account come into contact with the hops or they may be irreparably ruined. If a steady and unvarying temperature of 32º to 33º is maintained good results may be expected. Considerable changes of temperature and air movement should be avoided.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 186.

Having seen analyses made in the early 20th century, I’ve seen hard proof – in the form of alpha and beta acid content – that the deterioration wasn’t enormous, at least in the first couple of years. And way less than in hops stored warm.

“It is remarkable in what an excellent condition hops may be preserved providing they are of a suitable quality when they start. The temperature must be maintained at the correct level. We sampled some Worcester hops of good growth and management, some time ago, which had been in cold storage for eight years. They might easily have been mistaken for yearlings! It is very necessary that they are placed in store at the correct age, that is to say, just after the hop has passed through what may be termed its natural sweat in pocket. This takes place some three or four months after being gathered. Certainly not later than six months.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, pages 186 - 187.

By “yearlings”, he means hops not from the last season, but the one before it.

Here are those numbers:

Analyses of Fuggle's hops during storage
	cold store			warehouse
storage period	alpha resin	beta resin	preservative value	alpha resin	beta resin	preservative value
	6.28	8.6	91.5	6.67	9.26	97.6
5 months	6.22	8.2	89.5	5.83	9.17	88.8
9 months	5.72	8.25	84.7	4.72	9.34	78.5
14 months	5.84	8.54	86.9	3.48	8.64	63.6
19 months	5.15	8.92	81.2	3.21	9.9	55.1
Source:
"Brewing Science & Practice" H. Lloyd Hind, 1943, page 349

But you shouldn’t just throw any old hops in the cold store. Because, after all, it cost money to keep hops cool:

“It is unreasonable to expect any benefit commensurate with the outlay if the store is filled with hops of poor quality, or if the resins have already hardened to a considerable extent. We know of several instances where this has been done, with the result that a wrong and unmerited opinion has been formed of the cold storage process. The mistake is often made, too, of exposing hops, which have been in cold store, to ordinary temperatures and surroundings too long before use. This is another abuse of the system. A week or ten days at the most should be the limit of exposure, for afterwards the resins rapidly begin to harden.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 186.

This is a fascinating point:

“The introduction of cold storage for hops has resulted in a levelling of prices. Advantage can now be taken of a season when hops are of good quality and plentiful, whereas previously the brewer was at the mercy of prevailing conditions, even if unfavourable.”
"Brewing Theory and Practice" by E. J. Jeffery, 1956, page 186.

I plenty of numbers on the price of hops. Let’s see if it’s true that prices didn’t vary so much from year to year.

First in the early 19th century, before cold stores:

London Price of Hops per cwt 1800 - 1855
Year.	£ s. d.	Year.	£ s. d.	Year.	£ s. d.	Year.	£ s. d.
1800	17 17 0	1814	8 8 0	1828	5 12 0	1842	4 8 10
1801	5 18 0	1815	7 10 0	1829	8 8 0	1843	6 0 9
1802	10 12 0	1816	13 13 0	1830	12 8 0	1844	7 3 0
1803	6 6 0	1817	27 0 0	1831	5 18 0	1845	6 10 0
1804	5 5 0	1818	7 0 0	1832	8 13 0	1846	5 0 0
1805	8 0 0	1819	4 8 0	1833	7 4 0	1847	3 10 0
1806	7 0 0	1820	4 4 0	1834	6 3 0	1848	2 15 0
1807	5 10 0	1821	4 15 0	1835	4 15 0	1849	7 10 0
1808	5 18 0	1822	4 4 0	1836	5 0 0	1850	3 10 0
1809	4 4 0	1823	13 0 0	1837	5 1 6	1851	6 10 0
1810	6 0 0	1824	7 0 0	1838	5 17 0	1852	4 5 0
1811	6 6 0	1825	19 0 0	1839	4 10 0	1853	11 11 0
1812	13 8 0	1826	5 0 0	1840	13 11 0	1854	20 0 0
1813	8 8 0	1827	5 0 0	1841	6 6 0	1855	- - -
Source:
"A Practical Treatise on Malting and Brewing" by William Ford, 1862, page 289.

You can see that there was a fair amount of jumping about, particularly 1822 to 1825, 1839 to 1842, 1852 to 1854. This was a period without inflation. Yet the prices vary by about a factor of 10 from the most expensive year – 1817, £27 – and the cheapest – 1848 £2.75

Now here’s WW I on:

Price of hops per cwt 1918 - 1960
Year	Average Price of English Hops	Year	Average Price of English Hops	Year	Average Price of English Hops
£ s. d.	£ s. d.	£ s. d.	£ s. d.	£ s. d.	£ s. d.
1918	18 15 0	1933	16 10 0	1947	23 10 0
1920	19 10 0	1934	9 0 0	1948	25 15 0
1921	19 10 0	1935	9 0 0	1949	26 10 0
1922	12 0 0	1936	9 0 0	1950	21 0 0
1923	14 10 0	1937	9 0 0	1951	26 0 0
1924	10 5 0	1938	9 0 0	1952	28 3 0
1925	10 15 0	1939	9 10 0	1953	27 10 0
1926	11 5 0	1940	12 0 0	1954	29 0 0
1927	12 10 0	1941	15 0 0	1955	27 8 0
1928	11 16 0	1942	17 10 0	1956	35 2 0
1929	5 0 0	1943	18 0 0	1957	27 15 6
1930	4 15 0	1944	20 0 0	1958	27 5 6
1931	7 5 0	1945	21 0 0	1959	32 11 0
1932	9 15 0	1946	22 10 0	1960	30 18 6
Sources:
1955 Brewers' Almanack, page 63.
1971 Brewers'Almanack, page 54

There’s some instability in the 1920’s, but from 1934 on, there’s not much movement. If you ignore the inflation of the war years.

I should like up the details of hop control in WW I and after. They sort of nationalised hop sales to stop all the farmers going bankrupt when demand collapsed in the later war years. That probably had some effect on prices. But I can’t be arsed at the moment.

I have been arsed. These were the rules:

"The prices in the years 1918 to 1924 were fixed by the Hop Controller, and from 1934 onwards have been determined in accordance with the Agreement between the Brewers' Society and the Hops Marketing Board. The Agreement also provides for a levy in addition to the price, the maximum being 10s. per cwt. No levy had been imposed since 1943.
                           
From 1917 onwards, the home production of hops was severely curtailed and controlled without compensation to growers, under war-time restrictions and imports of hops were restricted except under licence. These measure came to an end in 1925."
"1955 Brewers' Almanack", page 63.

The effect of the rules after 1934 are pretty evident – rock steady prices. Looks like control rather than cold storage had the biggest effect on price stability.