Running Beers are beers that are imbibed fresh and can be brewed all the year around.

This British term is somewhat archaic but harks back to an earlier age of brewing. In the British Isles, before the role of yeast in fermentation was understood and before brewers knew how to take precautions against contamination, brewing was normally an activity undertaken largely in the cooler months. Everyone knew that beer brewed in summer was prone to quick souring. Grists were often mashed more than once; the first mashes produced a strong wort, resulting in stock ale that could be stored for the summer months in large wooden vats. The secondary mashes were analogous to the re-steeping of a once-used teabag; they produced a lighter “small” beer or “running beer” for immediate consumption. The beer was too light in alcohol to keep fresh for long, but then it didn’t need to.

In England there developed the practice of mixing together a stored stock ale, which would often have sour and fruity flavors from the presence of wild Brettanomyces yeast and other microflora, with a fresh “running bitter,” often only several days old. Greene King’s Strong Suffolk is a surviving example of this practice.

Building on Louis Pasteur’s pioneering work in the mid 1800s, scientists such as Horace Tabberer Brown, who started work at Worthington’s Brewery in Burton in 1866, began to focus on beer spoilage. Brown believed that spoilage was caused by an organism called Saccharobacillus pastorianus. Brown’s scientific work and that of others revolutionized brewery sanitation, enabling beer to be produced all year around. Summer-brewed beers no longer suffered from severe infection, and the terms “running beers” or “running bitters” came to represent lighter beers that were fresh and brewed all year round. Such beers required very short maturation and could be served little more than a week after they’d been brewed.