I don't have a proper food processor, just a little baby-food-sized one, so when I made Alton Brown's all-oats oatmeal cookie recipe before, I used half oat flour and half rolled oats. They were perfect, so I'd like to repeat them for my friend with celiac disease. I found gluten-free rolled oats, but the only oat flour I can find is labeled "may contain traces of wheat." Is there a way I can make rolled oats into flour with something other than a food processor?

  • 2
    Not sure if you've asked your friend, but its possible "traces of wheat" isn't actually a problem, it'd only be a problem if you actually had non-trace amounts of wheat. (Health questions like that are beyond our expertise).
    – derobert
    Commented Dec 24, 2016 at 6:53
  • There are some people for whom even trace amounts of wheat gluten are a serious problem, so it's important to check.
    – pjc50
    Commented Dec 24, 2016 at 14:04
  • @derobert: my friend was diagnosed less than a year ago, so she's still figuring things out, but the most recent blood test showed low-level gluten exposure, so right now, even "traces of wheat" is off the menu.
    – JPmiaou
    Commented Dec 24, 2016 at 16:19

5 Answers 5


You could use a mortar and pestle, if you have a good (and large) one - though it would take a lot of time and grinding to make it work, and probably small batches to fit your mortar and pestle size, it is doable, especially if this is a one-time use. you would probably not want to do this often, though.

You might try a blender, it's very similar to a food processor if you happen to have one. I would not recommend an immersion blender, as the oats (and flour) would fly everywhere (as opposed to liquid which holds together a bit more), but a regular blender should work well (also, keep it covered, though).

If you have a coffee grinder, that's also a possibility - it is intended to turn beans into powder, this is just a different grain. You might want to make sure it's quite clean unless you want coffee flavored cookies, though.

And final option, if you have a spice grinder, that should also work. Some people get a spare coffeee grinder for the job, or if you have a little hand crank grinder (like some people use for pepper or cinnamon or such), that would also work - though again, lots of work and small batch sizes, but possibly worth it for one time.

Additionally, if you toast the oats a bit, they should be dryer and easier to grind (and toasting gives a bit of flavor) - this will help especially if you're using one of the hand methods, like mortar and pestle or tiny spice grinder.

  • +1 for a blender, if you have a nice one it does a better job than a food processor.
    – Dan C
    Commented Dec 23, 2016 at 21:37
  • The Alton Brown recipe starts off with toasting the oats, so that's covered, but I don't have a jar blender, either.
    – JPmiaou
    Commented Dec 24, 2016 at 1:53
  • If I had a mortar and pestle like the ones they have at Hampton Court Palace's Tudor kitchens.... (I can't figure out how to attach a link to text in comments: hrp.org.uk/hampton-court-palace/visit-us/…)
    – JPmiaou
    Commented Dec 24, 2016 at 2:02
  • Thanks for the nice completist answer. I actually ended up using the baby food processor, in small batches, and resting it after every few minutes. It took most of an afternoon, and the result is crispier than the oat flour version. Next time, I'll make the trip to the specialty-natural-food store and hope they have GF oat flour.
    – JPmiaou
    Commented Dec 24, 2016 at 16:25
  • @JPmiaou - I'm glad you found my suggestions helpful. It's much easier, you're right, to pick up the right flour (or pick up the right tool) if you're going to be using such flour more often... some of the workarounds are alright for once or twice, but it's a lot of work each time, and easier to get a good product if you can.
    – Megha
    Commented Dec 28, 2016 at 2:55

We often use a coffee grinder to make almond flour for my son who is on a very restricted diet. We use a simple 19.99 blade grinder rather than a burr grinder. We've also used it to create powdered sugar from Xylitol and from ordinary cane sugar, and tapioca starch from tapioca pearls.

Good luck!

  • 1
    Should work nicely. It'll need to be done in small batches though; say 1/4 cup (20 g) max. The motors on those blade grinders will bog down if you feed them too much hard stuff at a time. Commented Dec 24, 2016 at 0:28
  • 3
    Something that's really helpful is using a flour sifter, and then re running the stuff that didn't make it through. It goes surprisingly fast when you get used to the grind-sift-grind cycle. we can process 2 lbs of almonds into almond flour in about 20 minutes using the coffee grinder and flour sifter.
    – Paul TIKI
    Commented Dec 27, 2016 at 14:20

Use a sift. It may take long, but the result is fine powder. Take some rolled oats and place it on the sift. Put the sift on top of a bowl or container. Rub the oat against the sift. After a while, you should have oat flour.

  • 2
    Thanks for the suggestion, but I don't know of a tool that has fine enough holes to make powder that's also strong enough to stand up to having rolled oats mashed through it. I certainly do not own a sifter or sieve that would suit. Can you find a picture of the sort of tool you have in mind?
    – JPmiaou
    Commented Dec 2, 2019 at 16:57
  • It’s called a “sifter” and some call it an “flour sift” because generally that is what it is used for, to sift flour. I hope this helps .
    – user99505
    Commented Jun 7, 2022 at 18:35

I just buy oats from my local supermarket and then I turn it into a flour for making my morning porridge in the microwave. The result is a creamy delicious porridge with bananas or tinned fruits, that I enjoy all the year around and never get fed-up with it.

I found the best way to turn oats into flour, is by using a blender on fast speed or as I do, by using a 400 Watts Braun hand blender, this too on fast speed.

When using the microwave to make your porridge, blend the four into some COLD milk, then stir in hot water, but not too much, otherwise you will end with a watery porridge and not a thick creamy porridge.

  • 1
    hand blender == immersion blender Commented Aug 3, 2018 at 14:07
  • 1
    And how exactly does one use an immersion blender on a completely dry ingredient like rolled oats? I think mine would sieze up within minutes if I tried that.
    – JPmiaou
    Commented Aug 4, 2018 at 16:47
  • 2
    Hello, and welcome to Stack Exchange. The original poster was asking about dry oat flour, not a pureed liquid. Commented Aug 5, 2018 at 3:58

An ordinary flour sift works. You just have to be patient. It takes a long time and you can't press to hard. Perform a sort of stir, rub motion.

  • 3
    A user named "Anonymous" gave much the same answer in 2019, above. I still don't know what sort of tool is meant by "ordinary flour sift", though. Nothing I've ever encountered would seem to fit the bill, so echoing my comment from several years ago: can you include a picture of what sort of thing you mean?
    – JPmiaou
    Commented Jul 22, 2021 at 7:07

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