One of the myths that's hardest to permanently kick into history's long grass is that beer exported to the tropics had to be strong. It persists despite plenty of evidence to the contrary. Below you'll find yet more.
"Keeping Small Beer.That's quite a claim, from Mr. Cunningham, that his Small Beer would remain sound "even in any part of the West Indies". I suspect most modern brewers would struggle to keep their beers in good condition in a tropical climate for any length of time without refrigeration.
WILLIAM CUNNINGHAM Brewer at Dundee, late a partner and manager in the extensive Brewing Company at Glasgow, begs leave to inform the public, and his friends, that he continues to brew SMALL BEER that will keep through the most sultry summer months, in the greatest perfection.— The excellency of this Small Beer is such that when all other kinds become sour and useless, the above small beer stands the heat of any climate; the liquor retaining its original taste, flavour, and colour in the warmest, even in any part of the West Indies ; —it has been much admired as table-drink for taverns or private families.
The Small Beer has also given intire satisfaction to ship masters who make voyages to any part of the West Indies ; but as no great quantity is made without being bespoke, Mr Cunningham wishes those who favour him with their orders, would do it before the brewing season is over, as it is not fit for use, either for home or foreign consumpt, in less than six weeks from the date of the commission. The Small Beer is sold at 3s. 9d. per dozen, bottles, &c included, or 24s. per hogshead.
Mr Cunningham also brews PORTER, allowed by the best judges not to be inferior in quality or Savour to London Porter: and as his machinery and materials are well adapted to that branch of manufacture, he flatters himself, the public, upon trial, will find it as good as any brewed in England, notwithstanding the many prejudices against Scotch Porter, which he now hopes are pretty much removed.
The prices of the several articles he manufactures are as follows, viz.
The above Keeping Small Beer, 24s. per hogshead.
Porter, from £2 12s. to £3 3 s. per hogshead.
Strong Ale, from £3 to £3 10 s. per hogshead.
Commissions from either town or country, directed to Mr Cunningham at Dundee, will meet with a ready and careful dispatch."
Caledonian Mercury - Monday 22 March 1773, page 4.
You have to consider the name for an explanation as to how a relatively weak drink could stand the heat. It's call Small Beer. The article dates from the 18th century, a time when Beer meant something specific: a malt liquor that was heavily hopped. It's also called Keeping Small Beer. Keeping, or a malt liquor meant to be kept for before drinking also implies extra hopping.
London and Country Brewer tells us something about how Small Beer was brewed in the 18th century. Often it was brewed from the later runnings of a stronger brew. But, especially when a better quality product was required, it could also be brewed "Intire", that is where all of the wort produced was used for Small Beer.
"'Tis therefore that some prudent farmers will brew their Ale and Small Beer in March, by allowing five or six bushels of Malt, and two Pounds of Hops, to the Hogshead of Ale; and a Quarter of Malt, and three Pounds of Hops, to five barrels of Small Beer. Others there are, that will brew their Ale or Strong Beer in October, and their Small Beer a Month before it is wanted."Assuming 60 to 65 brewers pounds of extract per quarter of malt, that would give 5 barrels with a gravity of around 1035º.Note that the book also recommends keeping Small Beer before use, though two weeks less than the minimum recommended by Mr. Cunningham.
London and Country Brewer, 1737, page 71.
Moving on to the Porter, in the 1770's, that usually had a gravity of around 1070º*. Which would tally with it being about double the price of the Small Beer, after taking into account the tax. In the 1770's, that was 1s 4d for Small Beer, 8s for a Strong Beer (like Porter). 24s minus 1s 4d is 22s 8d; 54s (£2 12s) minus 8s is 46s.
Scots drinkers seemed to have some trouble being persuaded that locally-brewed Porter was as good as that from London. Was that pure prejudice or was there some basis to it? We'll probably never know. It is clear that Scottish brewers struggled to sell their Porter and that drinkers preferred the stuff from south of the border.
* "Statical Estimates of the Materials of Brewing" by J. Richardson, 1784, page 150.