I particularly like the way some of the measures forced on brewers balanced each other out. Gravities fell, but the amount of adjuncts was reduced.
The perennial need for economy in shipping space for the purpose of bringing in food to England has led, among other things, to the use of barley flour in bread. One consequence of this was pressure, very strong pressure, from the Ministry of Food to get the brewing industry to replace 10 per cent of its barley with oats. Already flaked barley was being used by many brewers as a wartime device. Actually the barley so flaked was usually of good malting quality and simply could not be malted because of labor difficulties. It probably also saved fuel. By the use of flaked barley as a malt substitute, the extract provided was over and above that available from the restricted supplies of malt and sugar. With the release of barley for other uses by the Food Ministry, flaked oats and not flaked barley were slated for future use, although malted oats are being preferred in a few cases.
Flaked barley and oats have been manufactured by a process involving crushing, wetting, cooking wet up to 300-500°F and finally drying. Neither the germs nor the husks are removed. The enzymes are destroyed, but the starch is only slightly gelatinized. Neither of the flaked materials has presented serious technical difficulties. For the most part brewings have been normal, the change-over from flaked barley to flaked oats being scarcely noticeable in the breweries which had been using the former. Perhaps the chief problem has been concerned with securing a proper mixture of malt and oats in the grist, and special devices have been introduced for this purpose. Grinding times have had to be increased. Some brewers use ordinary raw oats which must be finely ground for them in a flour mill. Careful mixing with the malt grist is still necessary. Since flaked or raw oats yield only about two-thirds as much extract as malt, almost 15 per cent is needed to replace 10 per cent of barley in the grist. Apart from this, flaked oats are more bulky than malt, so that brewers who have already been using their mash tuns to full capacity need an occasional extra brew in some cases.
One advantage which has resulted from the use of flaked oats is that the considerable quantity of husk contributed has improved and hastened drainage of the wort from the mash tun and has thereby compensated largely for the loss of the bold-husked California malts no longer available. Flaked barley is less serviceable in this respect. Very few, if any, British brewers use a mash filter, and the time taken to sparge and drain mash tuns is a serious item in the day's brewing, that with labor shortages and blackout difficulties.
British brewers use malts of diastatic power 25° to 45° Lintner, which must seem incredibly low to the American brewer. Nevertheless, these malts are able to digest the increased amounts of non-malted adjuncts such as these flaked materials. No doubt the steady improvement in English barley, resulting from research and judicious buying in the trade during the past twenty years or so, has helped. The crops of the 1938 and 1939 seasons were excellent, those of 1940 and 1941 not so good. The chief objection to the 1942 crop was the generally low extract obtained from the malts, yet the diastatic power of these malts was as a rule high. Perhaps this has helped the digestion of flaked oats and ground, unflaked oats this year. Of course, it is the alpha-amylase of the malt that is mainly concerned, and the Lintner values normally determined in Great Britain tell us little directly of this.
"Wallenstein Laboratories Communications, December 1943, Volume VI, number 19" pages 155 - 156.
The government were very keen to get brewers to use oats. Partly because of a bumper crop in 1942. Also, I suppose, because barley was easier to slip unnoticed into bread. I wonder if the flaked barley that makes up 20% of the grist of modern Guinness was of malting quality? Somehow I doubt it.
See there's another example of measures balancing each other out. The husks of oats made up for the loss of husky Californian malt in the grist. See, there's another reason for the use of malt made from foreign barley in British beers. The coarser husks helped mash-tun drainage. Using raw oats seems a bit weird. Especially as brewers couldn't grind it themselves to the required flour. And wouldn't flour be likely to cause a stuck mash?
We also learn of the effect of these substitutions on the finished beer. Dryness. I can understand that. But what does "slight loss of character" mean? Blander, less flavoursome? It's surprising how little impact 15% oats appear to have made. Though I know brewers weren't very keen on using oats. But they're a conservative bunch often, brewers. Perhaps it was just prejudice rather than real objections. It would be nice to have the opinion of ordinary drinkers on the effect of oats on their favourite. Maybe they were happy enough at having a beer at all to worry about any changes in flavour.