Today in 1951, US Patent 2547988 A was issued, an invention of Hilton B. Levy, Arthur L. Schade and James S. Wallerstein, for his “Process For Improving the Foam of Fermented Malt Beverages and Product Obtained Thereby” for beer bottles. There’s no Abstract, although in the description it includes this summary:

The present invention relates to fermented malt beverages and more particularly to beverages of this type characterized by the capacity for forming a. stable, that is, a long-lived foam.

It is accordingly the general object of the present invention to provide fermented malt beverages Whose foam-head is longer-lasting in character than the foam-head produced by the normal components of these beverages as at present manufactured.

It is a further object of the invention to improve a persistent or enduring foam which he lasting qualities of the foam-head of fermented beverages by adding to such beverages at any suitable time in the course ,of their manufacture, but preferably after the fermenting and initial or coarse filtering, but prior to the storage period, a small quantity of a soluble non-toxic carboxy-methyl cellulose, preferably in the form of its alkali metal salt, such as the sodium and potassium salts.

We have now discovered that the foam of beer may be prolonged in a simple and economical manner by the addition to the beer of, small amounts of a water-soluble, heat-stable form of carboxy-methyl cellulose, as, for example, the

sodium salt of such material. This is commonly called cellulose gum, and, is a completely harmless and edible material. When solutions of, for example, sodium carboxy-methyl cellulose are added to beer in a concentration of 5 to 200 parts per million, the duration of the foam is greatly increased and a persistent froth is produced which endures for as much as several hours. Preparations of the sodium carboxy-methyl cellulose are particularly valuable when they are of a high viscosity type, and they increase the foam duration period many times.