[Mod: distilling is normally off-topic here, however, this question could equally be about making beer, since the primary subject is mashing/sparging and spent grain, so I'm keeping this question open so long it doesn't touch on distilling.]

I have been reading about the whiskey making process, but I do not make it. From what I understand, in very basic terms, a barley soup is made, and the water is drained off. This water contains enzymes etc from the barley, and this water only content is fermented, and so on in the process.

While Im sure this is hardly accurate it may be a general approximation in layman terms. If there are fundamental errors of understanding, please correct me. But Im understanding that the actual barley kernals are separated from the mix before fermentation.

My question revolves around what is left of the barley after it is separated from the mixture. Are they whole? Do they melt into the water leaving just waste behind? Something else?

Does this leftover waste have a term I can look up to find more about?

Update: I am not looking for things to do with this waste.

  • Have a look at my question on wheter whisky is made from beer, from a couple of days ago. In special, the linked article on Elliott's answer should be very useful. Commented Feb 22, 2013 at 9:28
  • I read all that. Dont see how it helps. Im specifically looking for the barley waste, not generally how to make whiskey?
    – Jon
    Commented Feb 22, 2013 at 9:45

3 Answers 3


If you're looking for a more technical description, you want to look into the process of "mashing". Beer mashing and spirits mashing operate on essentially the same principles.

For a typical barley malt, roughly 80% of the mash by weight will be converted into sugars. In other words, if you mash with 10 pounds of malt, roughly 8 pounds will end up dissolved in your wort and 2 pounds will remain behind as solid chaff. Most of it is fibrous husk material.

Spent grain doesn't have much nutritional value for humans, but it is frequently fed to livestock. Many breweries burn it as fuel, as well.

  • Keep in mind that after mashing and lautering the spent grain is wet, so it will subjectively weight a whole lot more than the 20% figure would suggest!
    – bk0
    Commented Feb 22, 2013 at 17:28
  • Indeed. Plus, the 80% figure assumes that you rinse the grain sufficiently to remove all of the sugar.
    – MalFet
    Commented Feb 22, 2013 at 17:30
  • How much water would be used with 10 pounds of malt? Roughly as an example for a wort to make whiskey from?
    – Jon
    Commented Jan 27, 2014 at 17:07
  • @Jon this will vary wildly from one place to another. Also, which "used" you have in mind? That's a story for another question, but probably too broad for Q&A
    – Mołot
    Commented Sep 17, 2015 at 11:52
  • roughly would do. Also you can list as many of the "used" you want. Thanks
    – Jon
    Commented Sep 17, 2015 at 13:04

Since the process before distilling is basically the same as beer making, here is what happens:

  • You mill the barley and make your 'barley soup', the mash
  • You then drain the liquid from the soup (wort) and put that to ferment

Back on your soup kettle (mash tun) you are left with the barley kernels and husks. During the mash you extracted a (hopefully) large amount of the sugars from the kernels but some are still left behind as unconverted starches.

As far as I know, the term for that is 'spent grain'

  • thanks for that. So you mill the barley 1st? Is must be a coarse milling to be left with kernals and husks?
    – Jon
    Commented Feb 22, 2013 at 10:16
  • thanks for the spent grain. wiki says it consists of fragments of endosperm. Fragments would indicate that most of the actual barley kernal has been dissoved into the mix? Would this be accurate?
    – Jon
    Commented Feb 22, 2013 at 10:19
  • Yeah, the barley is milled or crushed, depending on the type of mill used, the mill is coarse as we want the barley husks to be as intact as possible, since they act as a 'filter' for the mash. In my opinion, when looking at my spent grains, a lot of fragments are left behind. They look a bit different though, kind of gelatinous/transparent. Wouldn't know how much is left though. Commented Feb 22, 2013 at 10:56
  • Are you planning to get hold of those to reuse somehow? As far as I know most of the spent grains produced by the big breweries goes to feed cattle, but some burn it to produce energy Commented Feb 22, 2013 at 11:00
  • Im not looking to buy some. I am trying to estimate how much of the actual grain goes into whiskey versus just the flavours etc. The "proof in the pudding" would be the % of kernel left after taking the water out.
    – Jon
    Commented Feb 22, 2013 at 11:09

Once the grain has been soaked and drained (usually 3x), and all the good stuff pulled out and separated into a liquid that is called the 'Wort', that excess grain is called the 'draff' and has proteins. They mix it will cattle feed and sell it to farmers.

Here is a great article I found on all the extra bits from a distillery. http://peakperspective.com/whisky-wise/whisky-co-products-the-extra-bits-bobs-part-1/

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