Of Target and Twains
Below are references that deepen the discussion in my first part.
Basically, I show that the terms hopsack and hessian have been used in different senses, sometimes to mean merely a fresh hoppiness, but other times to suggest a separate quality, akin to the odour of jute or burlap.
Where a separate quality is meant, I see three possibilities.
1) The term is just metaphor, so a particular, maybe non-typical, characteristic of hops strikes the reviewer as evoking the earthy burlap smell.
2) The hops in the brew had some odour of jute attached from the hop pockets or bales they had been stored in.
3) The jute communicated some taste directly to the wort, by immersion. This might occur if the pockets, or smaller canvas bags holding hops, were placed whole in the kettle for steeping.
Whether no. 3 was ever done in British brewing I cannot say, but it seems likely that sometimes it was (is?), if only because some craft brewers today use bag steeping to hop the beer (a la teabag to make tea). Where I’ve seen it – actually I’ve done it – the bags are pocket-like nets made of a neutral, man-made material.
The references below also confirm that the aromatic qualities of jute, and some coffee, derive from a compound, phytane, in certain oils. This makes sense as mineral and other oils are used to process jute fibres into sacks. Originally, whale oil was used for this purpose.
In 1997 Michael Jackson stated in his Pocket Guide to Beer that Adnam’s Broadside, a pale ale, “blends hoppy, dryness and hessian notes”… Use of both hoppy and hessian suggests separate qualities.
Also from the Pocket Guide to Beer, Harwood’s Porter, made then by Guinness in London, had a “hint of hop-sack aroma”.
Again in 1997, an article in Decanter magazine reviewed different hops used in classic British beers. It described the Target hop as having “hemp”, “hessian” and “hop-sack” aromas. (I can’t tell the author from the extract in Google Books).
Woodsy qualities are often associated with traditional English hops, and a mineral or earthy quality seems related.
A 1990 book by Ian Niall, English Country Traditions, states that cider can be filtered through hessian or straw, with the former being preferable as not communicating an unwanted odour. While ostensibly suggesting jute is neutral, this may not be the case, but rather that country cider makers liked the taste it conveyed.
(This book seems, by some error, to be juxtaposed with another, unrelated volume).
In the 2011 Oxford Companion to Beer, ed. by Garrett Oliver, the entry on dry-hopping defines “hop-sack aroma” as simply a fresh hop flavour, arising especially from the monoterpenoids in hops. This usage again views the term as purely metaphorical. Yet as we’ve seen, writers on occasion have used hessian and hopsack to indicate qualities separate from those usually associated with hops.
In the 1990 text Flavour Chemistry: Thirty Years of Progress, the authors state that some jute sacks feature an “off” mineral oil flavour, from phytane, as does some coffee from India. It is not clear if the coffee tested had been stored in jute bags.
While the phytane is typed as an off-flavour in this perspective, it is consistent with many other accounts that state jute cloth can have a noticeable, characteristic scent. It is this smell some beer reviewers notice in beer as separate from a hop quality, or normal hop quality. Possibly it arises from yeast or malt although we think it more likely the hops carry the taste.
This 2008 entry in the website Science Direct gives more background on phytane, considering it a key characteristic of petroleum oils.
Finally, a recent article by Vincent Ehret on the “Beer Flavour Wheel” is useful in that the terms I’ve considered, hessian and hopsack, are not mentioned. I’ve reviewed a few other wheels, and don’t see them there, either. This may not be a complete survey, of course.
Ehret gives useful background on the origins of this professional tasting tool, which goes back to the 1970s.
I think it quite likely that hessian and hopsack were introduced by landmark consumer beer writer Michael Jackson. They belong, in other words, to the creative or imaginative side of beer writing, not the science side. Not that there isn’t a close connection between the two.
Brewing was ever a twain that met.