Recipe: Spent Grain Flour

As featured in the Spring 2022 Brewers Journal.

Brewing can be very wasteful with all the water and grain used. An awesome way to cut down on the waste of your brewing process is to resuse your spent grains. It may seem overwhelming dealing with a bunch of wet grain, but it can be a very quick and awesome way to add unique flavour to your cooking. I am gonna go over a few ways to process your grain efficiently and safely using what you already have in your kitchen.

The most important thing is to process your grains right away. If you let your grains sit for too long, the moisture in them can cause mold growth or other pathogens. If you're not ready to deal with your spent grains right away, you can always freeze them on a sheet pan and thaw them when you are ready.

There are three main methods which I'll go over. Freeze drying is arguably the easiest out of the three, followed by dehydrating, and oven drying.


Freeze Drying

By far the most foolproof. Unfortunately, it is the most out of reach for people because of the equipment needed. Most people don't have a freeze dryer. What I love about this method though is that you can spread all of the grains on the trays and turn on the machine and it will be ready in the next 2 days. No need to babysit.


Another great option if you have access to one. There are also some affordable dehydrators available online, or at a variety of department stores. Most dehydrators have holes big enough for the spent grain to slip through, so to help mitigate this use parchment paper cut to size and place spent grains on top. In the specific dehydrator I used, it had a hole in the middle of the tray, so I made sure to cut a hole in the parchment in the same space to allow air flow. I then set the temperature to 105F (40C) and left it on over the weekend.

Oven Drying

By far the most tedious method, but is the most attainable without buying another machine. For best results, turn your oven onto the lowest setting possible (ours was about 160F or 70C). Spread spent grains on a baking tray that is lined with parchment paper and put them in the oven. This method will take anywhere from 8 to 12 hours (or more!). Make sure to stir every so often, I suggest every 30 minutes in order to prevent burning and/or cooking. If your oven holds moisture, make sure to let the steam out. If, like me, you aren't able to finish dehydrating the spent grain in one day, you can always freeze the tray as is and start again when you have time. 

Flavour Comparisons

1. Freeze Fried: Has a softer mouthfeel. Tastes the most like the original grain. Optimal to still add a nutty flavour but remain netural.

2. Dehydrated: Has a more rough texture and tastes a little bland. Definitely my least favourite of the three.

3. Oven Dried: Has the roughest texture and tastes almost caramelized. A very pleasant taste for a recipe that needs deeper flavour.

Next Steps

Although you can use the spent grains whole after dehydrating, I like to turning them into spent grain flour. Using a blender, I will add the dehydrated grains and blend them into a fine powder.It can then sit in your pantry for months in an airtight container until you want to use them.

What to Make

You can make a ton of recipes with spent grains. My favourite way to find new recipes is to modify an existing recipe. First, I'll find a recipe that I think will benefit from the nutty flavour that spent grain brings. Then, I'll check the ingredients; if the recipe as one part AP flour, whole wheat flour, or white flour, I suggest replacing around 5-15% of it with your spent grain flour. If your recipe has a mix around 66-75% white flour, or 25-34% whole wheat flour, I suggest replacing all of the brown flour.

You can also replace ingredients like oats with spent grains. Overall, I suggest starting with a smaller replacement and gradually increase until you achieve your desired flavour without compromising the integrity. And don't forget that you will need to increase the amount of sweetener in the recipe, as the sugar that was in the grain is now in your beer!

Note: Make sure to write the grain profile on the container of the spent grain so you can know all of the allergens.

Ainslie's Favourites:

  • Spent grain pancakes: Using the 'Joy of Cooking' cookbook
  • Dog treats: Make sure there are no rice hulls or hops!
  • Fancy crackers: Again, make sure grains have no rice hulls!