The Oast Post

Dear reader,

Welcome to the tenth post, believe it or not! The next power of ten is 100, which is like two years away, and then a thousand. And don’t even get me started on 10^4, 10^5, etc. (in part because we’ll both be dead before both of those)

Today, in a PIVOT from the last few posts, we’ll be talking about a slightly more historical topic (don’t worry, it’s mostly 19th Century and on), concerning hops, and a shift away from a tradition that I don’t even think brewers at the time would have noticed - the death of the Oast. 

What’s an Oast

Pump the breaks there, cowboy! The real question is why is an Oast. Or who is Oast? How? The idea’s real simple: when you grow things, you generally have two options: use them immediately, or somehow transform them so that they’re shelf stable. What do Whiskey and Cheese have in common? Basically just one thing: their main aim was originally to extend shelf life (arguably, fermentation is the second thing). 

And while there are a wide variety of preservation options generally, all of which are interesting, from smoking to fermentation to salting (which was huge in the continental US but is somewhat less common than those other two), etc., for the vast majority of crops that aren’t fruits and vegetables (and that means legumes, cereal grains, even coffee), the name of the game is drying. That’s simply because microbes dig moisture - that’s it, and the solution is really that simple.

So how do we do this?

The Modern Solution

As we saw was the case specifically regarding malt in an earlier post, the straightforward method is to use air, with some target temperature and humidity (the latter in the case of malting, at least), to draw moisture out of the plant, here, hop flowers. While I suppose you could freeze-dry them, and while there are some whacky modern solutions to this problem like Cryo Hops (which I think are just normal hops whose oils are extracted like in the cannabis industry), and Steam Hops (which, again, I think use classical pelletized hops as their base), the far-and-away most common solution is the simplest and probably cheapest too, which is just drying them out.

So, how about that modern solution that the section header promised? Well, it’s mercifully quite simple on paper. Per the excellent For the Love of Hops book:

“Kilns in the U.S. Northwest consist of multiple sections within what are basically giant sheds. Conveyor belts carry the cones to the kilns after they are separated from the bines, and they are spread 24 inches to 36 inches deep. Heated air, forced through the bed from the bottom, dries the hops within six to eight hours.”

The book then describes heights and temperatures for different hops, but, like, who cares? OOO, can you tell me what that gear does? No, not that one, the smaller, less prominent one just to the left of where you’re pointing. It’s mostly in shadow. What does that one do, what’s its radius, and who do you go to for a replacement gear? What are the gear rep’s kids’ names?

But I will mention that they dry hops in the 130s-140s (˚F), and no, it’s not so hot that they lose the precious oils. Fair question.

And because the shape of these things is about to be important, here’s a surprisingly entrancing video of a modern hop processing operation. About a minute in you see what I think is kilning, and two minutes in you get to see Mack’s mom baling hops.

The Old Way

So clearly the goal is the same here: hot air, dry the hops, package them somehow, et voila. What’s different? Why Oast?

First of all, as mentioned in a previous post (I think it was the original Simulacrum response), in order to make hot (dry) air in the 18th century or thereabouts, you have to start a fire - no two ways about it. And indeed, the fuels in Oast Houses have ranged from wood to Sea Coal, which is to say, more modern and less-smoky carbon sources. This may have affected beer flavor, but since malt was also smoky, I doubt the hops-part of the smoke character was pick-out-able.

Second, hot air rises, so generally there’d be a netting of some sort, a filter, above the heat source, that holds the hop bed to be dried. And at this point I’ll steer those of ye desirous to see the diagram to this solid post, whose content I’m sloppily paraphrasing. 

And above that, there’s the familiar cone-shape of the “kiln” above the hops, and finally that peculiar and distinctive “cowl,” which...does one of maybe a few things. An earlier edit of this piece contained a pained dissection of the various descriptions of that famous cowl, and of course the answer was in Wikipedia - like a weather vane, it follows the wind, meaning the opening is opposite the wind, maximizing air flow. Pretty clutch.

So yeah, in summary, they’re big dumb kilns. I’ll note two more things: their vertical nature is interesting from an 18th century perspective, since breweries were often three stories in order to take advantage of gravity given the lack of electrical or steam-driven pumps (which, shockingly, existed in wealthier England). The second is that, instead of a mechanical baler, they had to have some poor schmuck just stand in the hop bag and tamp down the freshly-raining dried hops with his feet. Woof.

Also, my mom spent a sizable chunk of her childhood in Kent, like the famous hop, and where they (thus, and unsurprisingly) have a heavy dusting of Oasts all over the place. Neato!!

Also, if you live in California as I do, you’re in luck, since we have an Oast House that’s now an operating vineyard. Why not a brewery? Great question. Maybe they hop their wines. Maybe they kiln their grapes. I’m clearly upset by this odd choice.

Why Even Dry Them, Broh?

So, that’s an interesting question. On its head, the answer exists, and is emphatically delicious - fresh hopped ales, like this one. The problem, and the reason this isn’t super common practice, is also quite obvious now that you’ve made it this far (but hardly so if you hadn’t gone through this “why dry things” exercise), namely that you have precious little time to get fresh, unkilned hops into your boil kettle, super fast: “The hops must be used within a matter of days, preferably one day, after they are picked, or they will begin to rot” (For the Love of Hops). This limits the technique, even in the modern age, to those within, say, the same state as a hop farm, or breweries big enough to be growing at least a portion of their own hops. Or to homebrewers! And when I buy a small, two bedroom shack in 2053, you best believe five plants are going in: Lime and Seville Orange trees, Saaz and Fuggles bines, and maybe some Barley. Maybe some carrots, brussels sprouts, french beans, and garlic too. Potatoes. Sassafras and a wintergreen. It’s going to be mostly garden space.

And while I’m sure you could use this technique broadly, I’ve only really ever seen hoppy (Pale Ale and IPA) examples, which is obvious and reasonable. I’d love to see this with a Pilsner, however, or a Bitter, maybe even a Kölsch; definitely a Porter. If hops ever get very easy to grow, I expect this technique to become more commonplace due to the evident quality bump it offers.

Does This Matter?

You know what, fair question. I thought it would, I remember the Oast section of the hops book being longer than it is, but yeah it’s entirely inconsequential from pretty much any angle. I’ll try to pick a better horse next time, and thank you an extra amount for sticking with me this time, and pitching in your time on my beer-horse time bet, which we both lost, at about 9-to-1.

Cordially yours,

Adrian “Think this one’ll get retweeted?” Febre