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How to Clean Your Homebrew Grain Mill

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Have you ever cleaned your grain mill? Many homebrewers often neglect their grain mill, leaving it months, if not years, without cleaning. Like all of your other brewing equipment, however, your grain mill should be cleaned and maintained to prolong its life.

Cleaning your grain mill should be done after every use. Clearing away grain dust, debris, and husks with compressed air, a brush, and a lint-free cloth takes five minutes. These simple steps will keep your grain mill running properly. Every once in a while, a deep clean should be performed, as well. Disassembling your mill for a thorough clean and maintenance will keep it running like new for years.

How To Clean Your Grain Mill

Follow our guide for cleaning your grain mill to make sure you’re brewing the best tasting and highest quality beer.

Why Should You Clean Your Grain Mill?

Milling your own grain for homebrewing is a dusty process. Bits of grain and husks seem to get everywhere when milling. Of course, the majority ends up in your grain bucket, but your grain mill is usually left with a coating of fine dust and shredded husks.

Cleaning off this residue is important to maintain the longevity of your mill. Since grain has almost no moisture content, it’s not likely to smell or mold. For this reason, many brewers don’t bother cleaning their mill. But bacteria can still grow in the sugars of the grain. On top of that, a build up of caked-on grain dust can cause problems while milling.

Keeping your mill clean will keep it functioning properly and extend its life. You’ll also eliminate any risk of bacterial growth in your equipment.

When Should You Clean Your Grain Mill?

Cleaning your grain mill every brew day is highly recommended. It’s quick and easy, taking no more than five minutes. A light clean after each time you crush grain will keep your mill running smoothly and prolong its life. Plus, you won’t be storing away a dusty mill, keeping your garage or brew room neat and tidy.

Basic Grain Mill Cleaning Every Brew Day

Aftering milling your grains and mashing in, take a few minutes to clean your grain mill. All it takes is a few simple tools:

  • Compressed air
  • Brush (toothbrush or small paint brush)
  • Lint-free cloth
  • Vacuum (Shop vac preferred)

Follow these easy steps to ensure a clean and well-functioning grain mill.

Step 1: Brush away all grain dust and debris

Using a dry brush, clear away as much grain debris as you can from the mill’s base, hopper, and rollers.

Step 2: Use compressed air to blow the hard to reach areas

Using compressed air, either from a compressor or a can, blow away any remaining dust from the corners and crevices of the mill.

Step 3: Vacuum

Using a vacuum cleaner like a shop vac, quickly go over the mill, hopper, and base to suck away any lingering bits of grain.

Give the mill assembly a wipe with a lint-free cloth. It should now be free from all bits of dust and grain particles.

Step 4: Storage

After cleaning, store your mill in a dry area. Your mill will be nice and clean, ready for your next batch of homebrew.

Periodic Deep Cleaning Your Grain Mill

Performing a deep clean on your grain mill should be done at least yearly, or even every six months if you brew often.

In addition to the tools mentioned for the everyday clean, you’ll want to get yourself the following items:

  • Screwdriver for hopper removal
  • Food-grade mineral oil

If you know you won’t be brewing for a while, giving your grain mill a thorough clean before long-term storage is also a great idea. This will help prevent mold growth or corrosion.

Step 1: Detach the electric drill or hand crank

Most homebrewers use an electric drill to power their mill. Some brewers like to use a hand crank. However you power your mill, remove the crank or drill from the mill’s drive shaft.

If you have a built-in motorized mill, unplug it before cleaning.

Step 2: Clear away all debris

The next step is basically performing all of the routine cleaning, as we described above. Make sure you’ve removed all grain dust and debris.

Step 3: Disassemble hopper

Most grain mills come with a hopper, usually made of 4 sheets of galvanized or stainless steel. Unbolt and disassemble the hopper. Using a dry, lint-free cloth, wipe away any grain particles. Use a toothbrush or paint brush to lightly scrub off any stuck-on pieces.

Step 4: Thoroughly clean mill and rollers

Now that the mill is disassembled, the roller frame and rollers are easy to clean. Use compressed air to blast away as much grain dust as you can. Lightly brush all surfaces with a dry toothbrush. You may need to open up the gap between the rollers to clean hard to reach debris.

Wipe away any left over dust with a lint-free cloth.

Step 5: Oil bushings

Applying a small amount of food-grade mineral oil to the roller’s bushings will keep them turning smoothly. Add a drop or two of mineral oil to the end of each roller and give them a few spins. It doesn’t take much. Wipe away any excess oil that’s dripped down.

Step 6: Ressassembly

Once you’ve thoroughly cleaned your grain mill and lightly oiled the bushings, you should reassemble the mill for storage. If you’ve adjusted the gap size, remember to reset it back to the original position.

Store your grain mill in a well ventilated and dry space.

Final Thoughts

Eager to get on with the brew day, homebrewers often neglect to clean their grain mill after crushing their malt. Dedicating a few minutes during the mash or boil to lightly cleaning your mill will extend its life. Every now and then, a deep cleaning is a great idea to keep your grain mill good as new.

With a little bit of time and a few simple steps, you can keep your mill running like new and continue brewing consistent, awesome homebrew.

Frequently Asked Questions

Should I clean my grain mill with water or soap?

No, it is never a good idea to get your grain mill wet. Rust can form on a wet or damp grain mill, corroding the metal and rendering the mill unusable.

If your grain mill happens to get wet, disassemble it and dry thoroughly. Allow it to fully dry before reassembling.

How long will my grain mill last?

Grain mills are designed to crush through thousands of pounds of malt. Malted grain is very dry and hard, but most grain mills are built to withstand the difficult task of milling even the hardest of malt, like rye malt.

With proper maintenance, your grain mill should last at least 5 years, and most likely more than 10.

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