brewing

October 13, 2008 9:58 AM

Whisky filter: why don't distilleries use oats as the grain to make whisky?

I went on a distillery tour in Scotland and the grain used to make the whisky is usually malted barley and/or wheat. Why are oats never used as they'd be indigenous and presumably readily available? The tour guide didn't know the answer to the question so I'm wondering if anyone here does? My guess is perhaps oat grains can't be sprouted and malted, but that's only a guess. Any ideas?

posted by stenoboy to Food & Drink (12 answers total)

Well, oats can be malted. They're used in oatmeal stouts and some other beer styles (Atomium Grand Cru has it, and some other ancient-style Scottish ale recipes I've seen as well)
posted by mkb at 10:08 AM on October 13, 2008

Rye is also used (e.g. rye whiskey). And of course there's corn whiskey.

I suspect the reason oats aren't used is that the result doesn't taste good.
posted by Class Goat at 10:13 AM on October 13, 2008

For beer, yeah, oats apparently make a nasty brew. I suspect, then that anything distilled therefrom would be similarly nasty.
posted by MrMoonPie at 10:35 AM on October 13, 2008

Up until the 19th century, however, Irish distillers also malted oats. E.B McGuire, in his book, Irish Whiskey (1973), reports that oats were said at the time to produce a better flavoured whiskey.

The practice of malting oats died out when a duty was imposed on malt. Since the duty was assessed on a volume basis, and since oats swelled far more during the steeping process than barley, it made economic sense to abandon oats.
source

posted by exogenous at 10:40 AM on October 13, 2008 [1 favorite]

I'd guess the reason is for the two intertwined reasons of flavor and tradition.
posted by pmbuko at 10:45 AM on October 13, 2008

Oats are also difficult to malt compared to barley, and create a viscous mash that is difficult to handle.
I'm at this moment literally in the middle of mashing a 100% barely beer, so this question caught my attention!
posted by exogenous at 10:47 AM on October 13, 2008

Oats are used in Irish whiskey.
posted by jdfan at 10:48 AM on October 13, 2008

Oats aren't 'indigenous' to Scotland; they were carried there by the expansion of Fertile Crescent crops and agricultural practices. What you may mean is that they may be now commonly grown in Scotland?
posted by ZaneJ. at 11:06 AM on October 13, 2008

For beer, yeah, oats apparently make a nasty brew.

Blasphemer.

I'd love to try a whisk(e)y made with oats. Would be an interesting difference, I'm sure.
posted by dirtynumbangelboy at 1:29 PM on October 13, 2008

I'm aware of two difficulties with oats in brewing beer: one already mentioned is their tendency to increase viscosity (this can enhance the finished product in small quantities - oats are a classic ingredient in many stouts - but I understand in large quantities you get a really sticky, slimy mash that is hard to deal with), and I've been given to believe that they do not contain the necessary enzymes to break down their starches to fermentable sugars without the addition of other malted grains - so mashing straight malted oats would be a no-go. I've yet to brew with oats though so this is all book larnin'.

You can ferment alcohol from a lot of things and people have, from acorns to wild apples (the orchards the real Johnny Appleseed went around setting up in colonial America were for hard cider distilleries, if you believe what Michael Pollan has to say about it), but barley and wheat happen to work particularly well.
posted by nanojath at 2:22 PM on October 13, 2008

Oats do not make a nasty brew. Astringency & bitterness are traits favored by some in their drinks, after all.

Oats do, however, contribute so much mucilaginous protein to the mash that it can "seize up", preventing the wort from draining off. Imagine a bowl of oatmeal left for half a day... basically, it becomes rubber. For this reason, they are generally restricted to less than 25% or so of the total grains by weight - usually much less, even in the so-called "oatmeal stouts".

Now imagine that you take that blob of rubberized oat wort, and attempt to boil off the alcohol in a still. The bottom of the blob will burn before the damn thing boils. Bleh.
posted by IAmBroom at 9:23 PM on October 13, 2008

Oats are full of beta glucans. You can add a small amount to the mash for a wort (which you then distill to make whisky), but I don't think you could mash an entire tun of the stuff. It'd just be a gummy mess, the mash would stick and your run-off would trickle to a halt.

More importantly, oats don't have the enzymes necessary to convert the starch in the grains to sugars. You'd need at least some malted barley for the conversion (a bit like adding barley to a corn grist when making an American pilsener). Again, I'm not sure you could boil up a big ol' tub of oats with a small amount of barley without getting a gooey, porridge-like mash that'd stick as soon as you tried to drain it.
posted by obiwanwasabi at 3:20 AM on October 14, 2008