Here is the full text of a 140-page book on beer blending (coupage) issued in 1871 by Moniteur de la Brasserie, a brewing industry periodical published in Brussels, in French. The Moniteur and its publications had wide distribution in France as well and the blending book is addressed in fact to brewers of both nations.
Its full title is Livre de Poche de l’Apprêteur de Bières en France et Belgique. The sense of apprêteur is not easy to render in English, it means a “finisher” or final processor of a product. Today, especially in light of the (very few) actors in Brussels that continue this work, we would term them “blenders”. The book was meant to apply to this trade but also to brewers thinking of turning their hand to blending, or improving the blends they already made.
The Moniteur issued a series of books on different aspects of brewing, including the blending book (text via Gallica in France).
By way of background, the book appeared at a specific juncture in French and Belgian brewing history. Top-fermentation was still widely practiced in Belgium and the north of France. But bottom-fermentation, often styled Bavarian, was not unknown in these places. In fact, Paris counted numerous breweries making beers broadly in the Bavarian (dark lager) and Vienna (light amber) styles.
Britain, whose beers are mentioned periodically, was still vowed to top-fermentation, that is, mild and pale ales, porter, stout, and strong ale.
The book argues that the blending of beers is a necessary adjunct to the top-fermentation brewery. This is due to the frequent imperfection of the beers (at the time before modern temperature controls and yeast science), but also the desirability of achieving a consistent and pleasing palate for the public.
It is stated that the perfect beer doesn’t need blending – almost an echo of the theory of “entire” porter of the early 1700s – but in practice blending is necessary and salutary.
The book (no individual is credited) advises that a good blender can make greater profits than a non-blending brewer. The blender needn’t invest in expensive plant, simply enough store space for the beers and some simple manipulations.
The book reviews blending in various countries: Belgium, where lambic (aged 1-3 years) and (always young) March beer (bière de Mars) were blended to make Faro; Britain, for its porter; even Germany, which added young beer to aged lager to carbonate and freshen it (krausening).
The book explains how blending was practiced in Brussels to a high art, not just by middlemen, but by the bars (estaminets), and each often applied trade secrets of some complexity. That said, the book acknowledged that Brussels beers had a daunting sourness for many, and advised careful blending to offer the best advantages of young and old beers.
It was stressed that a good aged beer, and certainly a good blend, should not be sour in the sense of vinegar. French bière de garde should exhibit, wrote the author, tastes of lactic and even acetic acid but not taste of vinegar. A sour-sweet palate was advised.
The author noted in Belgium, even old lambic was often sent to the pub with sugar added, 1.5-2 kgs/250 litre tun.
Generally, sugar or syrup was necessary for all coupages, to induce a re-fermentation for carbonation and a creamy head. It’s similar to the U.K. practice of priming. (This is different from adding sugar to the brewing kettle or fermenting tank, and more supportable as a matter of palate and convenience, IME).
One fascinating statement confirms historical work published a few years ago by British beer historian Alan Pryor in the journal Brewery History, that when malt was cheap brewers made large quantities of beer for aging, and less new beer (meant for quick sale). In the obverse, more new beer was made and cut with the aged beer on hand, to drop the production cost. I discussed his work in this post earlier and identified further support, from America in that case, and also from the 19th century.
The book discusses blends of various types, not just of old and new beer, that is. The author has no objection to blending top- and bottom-fermenting beer. He states some German brewers do so who lack sufficient space to age all their output. This suggests, or to me, that so-called Schenk Bier, the pre-lager beer of Bavaria made in the winter for quick sale, probably originally was top-fermented.
There is much more in the book..