It's also a good lesson in not making assumptions. Look carefully at this recipe and you'll see that they weren't brewing what we know as Pale Ale.
See why I said it isn't like Pale Ale as we know it? No. OK, I suppose I'll have to tell you.
Here they draw off a hogshead of very fine pleasant straw-coloured ale from twelve bushels of malt, in the following manner, namely: They boil the water, then throw two parts of cold into the mash-tun, and the boiling hot water on that. They then put in the malt, half a bushel at a time. After stirring it till all is soaked, they cap it with malt or bran, and cover it close to stand three hours. They then look if the mash has sunk in the middle, which it sometimes does, and when this is the case, it shows the strength of the goods, and must be filled up level with boiling water, to stand afterwards for half an hour, when it is to be run off in a goose-quill stream, and returned upon the. goods again, by a bowl or pailful at a time, as fast as you can, from the cock; for then the liquor strains through the body of the goods, and at length comes very fine; otherwise you force the thick part down to the cock: this is called doubling, which is continued for half an hour; they then stop and let it stand for half an hour longer in winter, but not in summer. Four pounds of hops are rubbed very fine into the tun for the wort to run on. They take care not to draw it off too near, before they lade off more boiling water out of the copper, which is continued till they have their quantity of ale-wort; which, with all their hops, is boiled till the liquor breaks or curdles; they then empty all into large earthen long pans or coolers, which they work, when cold, with the same hops, altogether, in the following manner: They put a little bit of young yeast (that is, not above a day old) to a parcel of the liquor, and mix that with all the rest to work twelve or fourteen hours; and then directly strain it into the barrel, where they keep fitting it up with fresh wort, till it at length becomes full. When the fermentation is finished, they paste a piece of brown paper over the bunghole for a fortnight, which very much conduces to its fining, and then they bung for good with a wooden stopple. In this manner they draw their ale perfectly fine in three weeks or a month at most.
They never mash here above once in their strong drink, and seldom make small, on account of its cheapness; they, therefore, think that it turns to better account to leave a strength in the grains for feeding the swine.
"The town and country brewery book" by W. Brande, 1830, pages 196-198.
First off, the strength. A hogshead is 54 gallons and they're using 12 bushels of malt. Which is about 500 pounds. Even allowing for the fact that they were leaving plenty of goodness in the grains, that's a stack of malt for just a barrel and a half of beer.
A quarter of pale malt yield around 70 to 80 brewers pounds in this period. They couldn't have actually got anything like that because, well, you can't get a wort that strong. It would be somewhere around 1190º. More likely is a wort of around the maximum strength, around 1120º. Not sounding much like a classic Pale Ale, is it?
Then there's the hopping. Four pounds of hops for a barrel and a half of beer. That's 2.67 pounds per barrel. It may sound like a lot, but this is massively strong. Let's compare it with a couple of real Pale Ales. Reid IPA and BPA from 1839. They were hopped at 5.88 and 5.61 lbs per barrel. With gravities of just 1056º and 1057º. Or more than 20 lbs of hops per quarter of malt.
Whitbread's XXXX Ale of 1837 was a similar strength to this Barnstaple Pale Ale, at 1114º. That had 3.64 lbs of hops per barrel.
What's my conclusion? This beer is an Pale Ale in the 18th-century meaning of the term. A relatively lightly-hopped beer brewed from pale malt.