In my last post I discussed a “sand porter” advertised by two brewers in the Montreal area in the 1880s and 90s.
The most likely explanation for the term is that the porter was filtered through a sand bed, in order to be reasonably bright and stable in the bottle. Through the 19th century, recommendations appear to filter beer in sand (and other substances), probably as a spin-off of early water treatment.
The crevices of sand trap the yeast and protein particles, so the filtering works by physical action, as charcoal does, with a clarifying and purifying effect. The medium must be continually washed so the material can regenerate for use. Sand is virtually indefinitely re-usable, hence cost-effective and environmentally responsible. White sand was typically advised.
Today, among numerous other methods, diatomaceous earth (DE) is often used for close filtration, a sand-like, silica-based substance. DE is a better filter, as it is more neutral and traps more and smaller particles, but sand recurs for discussion among modern brewing technologists. One reason is that DE may pose certain health risks, cancer has been cited.
(The filtration issue has lessened in importance in craft circles, although much craft beer has been, and will continue to be filtered if only roughly).
The following references, among many more I consulted, will support the above. The second, an 1888 American bottling manual by Charles Sulz, covers more or less the period we are dealing with.
Sulz advises the sand filtering for light beers that otherwise would be liable to sour, versus strong beer that conditions by long standing but remains stable. It is interesting that he mentions molasses and sugar beers in this regard, as molasses may well have been used to bulk out the staple porter in Quebec. The old Champlain Porter, which I recall in the 1970s, had a light flavour of molasses.
Reference no. 1, an early 1800s British encyclopedia, offers a detailed discussion of beer filtering and advises sand for this use. A well-known engineer, Joseph Bramah, is cited, known among beer historians for his work on the beer engine or vacuum hand pump, associated with cask-conditioned beer.
Sand filtration was later superseded by DE and other methods, supplemented by pasteurisation. Still, the concept has never completely disappeared. Numerous studies continue to canvass its effects as compared to other materials, e.g., “Evaluation of a Substitute Filter Medium for Removal of Haze in Beer“, by Ma. Perpetua M. Marquez, Department of Chemical Engineering, University of Adelaide.
Sand porter is perhaps not the most elegant term, which may explain its demise in the Montreal market, but the process was probably more widely used than the name.