As I mentioned earlier, the food supply problems of WW I prompted the government to be very careful right from the start of WW II. They tried to ensure that as little food as possible was wasted. Even stuff that wasn't obviously food. Like waste yeast.
"Early in the war the salvage department of the Ministry of Supply invited the Institute of Brewing to go into the question of brewery waste products, and a committee was formed which collected the necessary information and made its report. Yeast was considered to be the most valuable of brewers' bye-products in view of the fact that one-half of its dry weight consists of readily digested protein while it also contains vitamins. Most of the surplus yeast in the large centres is utilized for human foods or is dried and used in the preparation of cattle foods. It was realized, however, that a good deal of the yeast from the smaller breweries in outlying districts and the smaller towns was not being utilized, and steps were taken to advise the farmers throughout the country of the value of yeast as a supplement to the pig food ration, with a view to overcoming this waste. Most towns and urban district councils organized a collection of household waste, and breweries in these districts had no difficulty in disposing of their waste yeast to them, and it is probable that Very little of this valuable foodstuff was wasted."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, pages 125 - 126.
The human food I guess would mostly be marmite. I didn't realise it was also used to feed animals, but I suppose that makes sense. There's no way you were going to persuade everyone to eat marmite. I wonder if it's still used in cattle food? Breweries produce a lot of yeast, far more than is needed to ferment subsequent batches. The excess needs to be disposed of somehow. Where does it go?
I mentioned that there were a host of wartime difficulties that I hadn't considered. Changes to the water supply is another one. It was all to do with the level of chlorination:
"For a number of years before the war the chlorination of water supplies as a supplement to nitration in order to reduce its bacterial content to a safe limit has been very generally practised, but the amount of chlorine present was usually too small to become noticeable and was never sufficient to have any deleterious effect when it was used for brewing. The quantity used during the war period, however, was often increased after damage of mains by bombing and much heavier quantities were necessary for short periods. No noticeable effect, however, seems to have been experienced by those breweries using the London supply. Although even an excess of chlorine is hardly likely to have any directly harmful effect either on yeast or beer, its effect on the pipes and mains through which it is conveyed does not appear to have received the attention it deserves. A case occurred in a town which had been severely blitzed, and it was found necessary to chlorinate the water supply to overcome suspected contamination. The writer found that this had been carried to excess, so much so that it had a corrosive effect on the copper-lined fermenting vessels of a brewery. Fortunately there is a simple antidote for chlorine and the necessary steps were taken to treat the water in the cold liquor tanks before any harmful effects occurred, but it is a matter that should be borne in mind, as others might not be so fortunate."
Journal of the Institute of Brewing Volume 52, Issue 3, May-June, 1946, page 126.
Is this still a problem? Mains water is often still very heavily chlorinated in Britain. I drink the tap water in Newark. It's like taking a mouthful of swimming pool. Hang on. I remember asking John Keeling about Fullers' water supply. He told me that they had to stop using their own wells because they became contaminated. They now used mains water which they first dechlorinated. I'd assumed that was flavour reasons but maybe it was really to protect their equipment.
That's the article itself done. Just the discussion to go. If I can be arsed.