The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Wolfgang/Komo mill stone safety?

persimmon's picture

Wolfgang/Komo mill stone safety?

Wow, what a great site with so much helpful info.  I really want to join the home grain milling tribe! Every 6 months, I spend hours researching mills online, get too confused and don't order anything...But I think I'm close...right now it's Nutrimill vs. Wolfgang/Komo.  Both seem like great mills, but on the downside I see it as micronizer vs. unknown millstone material.

My question is, does anyone really know what CERAMIC CORUNDUM is???? I googled it, and seemed Chinese company is a major supplier of some ceramic corundum. Has anyone come across any safety data on this mataerial?

Thanks for any advice!

blaisepascal's picture

Corundum is a name for aluminum oxide in mineral form.  It is hard, relatively inert, naturally transparent and clear.  When it naturally appears with impurities, it can be colored and is called ruby or sapphire. It's also called alumina.  Because of it's hardness and ready availability, it's a principle component in sand-paper, which is mainly some hard grit (like corundum) glued to a paper backing.  You could view the millstone as mainly some hard grit (like corundum) mixed into a ceramic clay and kiln-fired into a millstone.

As far as safety goes, all the Material Safety Data Sheets I've been able to scrounge up on alumina or corundum basically state that it's categorized as a "nuisance dust", and you don't really want to be breathing it or rubbing powdered alumina into your skin or such.  There's no real danger to eating it in small quantities.

Ria's picture

I have a WhisperMill; I think Nutrimill might have bought them out. I've had mine for over 15 years. I really don't think it matters what you get as long as it grinds grain. :)

I tend to grind about 5 lbs of whole wheat flour, a bag or two of popcorn, and 10 cups of rye flour at a time (stored separately of course!). It's quick, and then I stick the flours in the fridge. I rarely use the does its job, and then it goes away. I guess my advice would be, don't worry too much about what you get, just get one and enjoy! 



Nickisafoodie's picture

Same as Rea, have had my whisper mill for over 15 years, have run several hundred pounds thru over the years making 10lbs of dough at a time for 5 loaves, max that fits in myoven. 

Stones break down on a microscopic level and if the aluminum pots of the fifty's were linked to alzheimers, why take a chance on aluminum oxide, as inert as it may be?

Very happy with flour, usually 5lbs at a time that is done in a few minutes, moreover, the temp doesn't rise much at all, thus keeping the nutrients intact.  And flour is very fine, which I prefer, can be made courser. 

Nothing, I mean nothing tastes better than a whole grain loaf made from fresh ground flour, expecially when using rye in addition to whole wheat.  Store bought just doesn't cut it, even the high end flours like KS will taste stale by comparisson.  You'll never go back...  Good luck!!

persimmon's picture

Thanks for the input so far. I desperately want to believe blaisepascal and not worry about it. I had become quite attached to the idea of the Wolfgang/Komo. It looks so easy and compact. I was sure I'd finally join all of you in experiencing a delicious loaf unlike anything I've ever tasted before! Everyone's descriptions make me salivate with envy.

But I'm hesitant to put this man-made material in the "innocent until proven guilty" category. With further searches I found a site that talks of the production of making alumina based ceramics. I don't know if this is the same thing as ceramic corundum, but the additives look scary toxic and additionally bad for the environment. Of course I don't know the relative environmental impact of making steel burrs or plastic housing of the Nutrimill. Also the Schnitzer site talks about "new grinding edges" being constantly exposed with their corundum stones (they mention this as a positive). Despite assurances that it is trace amounts that end up in the flour and completely safe, I'm not sure I want to be eating the "old grinding edge". I'll have to ponder if I will turn a blind eye to it. Any other input or opinions are appreciated.

Nickisafoodie's picture

Forgot to mention one thing in my post above: When using my Whisper Mill, I usually add a fair amount of flax seeds to the whole grain and grind them together, gives a nice subtle flavor, plus very healty addition.  The Whisper Mill can easily handle this, whereas stone mills would likely not as the oil may clog the stones...  Can't argue about how pretty the German Mill is with its wood case, but I'm all for functionality...  thanks and good luck no matter what you pick, fresh ground rules!

Amadeus's picture

Based on my own experience, I would not grind any amount of flax seeds in the Whisper Mill, even mixed with 90% + hard/dry grains. I have done it with my Whisper Mill and within 1-2 years it stopped working. Has the sound of the motor began to change yet? In my case, the nice folks at WM (former, original company/owners) were kind enough to replace mine with another one without charging me a penny but advised me (politely) to not grind any oily seeds in the Whisper Mill anymore. I guess they have realized what happened right away, I am certain I was not the first, nor the last person to do it. Hope this helps.

bread_improver's picture

Thanks for this thread -- great to have found this forum.


While the Corundum from stone mills is factory-made, the mineral Korund -- a form of Al2O3 -- is quite common in the earth's crust and occurs naturally, e.g in granite.

There are forms of Corundum which are inert -- they don't react with acids or lyes , and the only way to get rid of them is to melt them again at about 2050 degrees Celsius (3700 F) -- so even if you ingest traces of it, it won't be able to do anything to your body -- that said, I don't know whether the Corundum used in ceramic mills are this inert.

Aluminum, on the other hand, is very reactive. I'm astonished that it should be linked to Alzheimers -- lots of people cook in aluminum pots, everybody uses aluminum foil in the kitchen -- but that doesn't mean that aluminum oxide would be.

Also, Corundum is the second hardest material known, second only to diamond. It's used in mechanical clocks and other applications where abrasion has to be minimal -- it is maximally resistant to abrasion.

Therefore, you are more likely to find traces of the burrs of a metal burr mill in your flour than of the Corundum in a stone mill. And the metal is more likely to do something to you -- steel contains nickel which some people are sensitive to, I for one.

I believe the mechanism in impact mills like the NutriMill also has metal parts? Again, you would have more abrasion from that metal than from the Corundum stones inside a stone mill.

Not that I think that abrasion is a major issue in either of them, there are obviously others, posted by many helpful people in other threads.

Thanks for posting this, anyway. Which mill did you go with, and how has it turned out?



sonika's picture

Today I just saw pictures of a grain mill, which the manufacturers claim its stones are diamond coated (the all grain 22). Would you, or anyone know anything about its abrasiveness? Which type of grain mill would you rate as the least abrasive, and what about the least harmful?

sonika's picture

Quote: "I believe the mechanism in impact mills like the NutriMill also has metal parts?"

Can you elaborate a bit more on this opinion please? I am looking to buy a grain mill and this might be helpful in making up my mind.

ElPanadero's picture

Your choice really depends on why you want a mill.  Is it for :

1.  Experimentation of using milled flour

2. The luxury of just having your own mill

3.  As a self-sufficiency strategy should flour become hard to get hold of in shops

The choices will, for one thing, determine whether you buy an electric grinder or a manual grinder or a grinder that has both ablities combined.  Another factor is where do you intend to use it?  In the kitchen or back out in a shed or garage and thus does it need to look "decent" on a kitchen work surface ?  Too many kitchens these days are littered with horrible chunks of plastic mechanical machines sitting there looking out of place and ugly.  Is this a consideration for you or do you just want soething functional and hang the looks?

Stones vs Steel Burrs is a regular debating topic amongst home grinders.  For myself I would favour stones on the basis that metal will heat up quicker and risk destroying some of the enzymes in the not to mention as they wear down, that metal must be going into the flour in some form.   Stones have been used for 1000s years.  You will find that each manufacturer cites different levels of what I would deem complete nonsense and "kidology" to try to steer you towards their products.  Steel Burr manufacturers will tell you that dug up corpses of ancient people show their teeth are ground down from eating flour with stone particles in it (laughable imo) and Stone manufacturers will tell you that Steel wears down easily and gets too hot. 

Steel grinders can grind a wider variety of produce I believe but stone grinders to me seem more natural and have a very long track record let's face it.  Windmills, watermills etc have been used for millenia.

A good array of fineness adjustablility is important imo to be able to create different things.  I use mine to make both fine flour as well as rough chopped rye to add to loaves or to sprinkle on top of loaves.  Another consideration is whether you may want to have the ability to flake too.  In particular oat grains (groats).  Flaked oats are great for making the freshest porridge, for baking oat cookies and the like and for sprinkling on the top of loaves.  Flaking machines are sold separately so buying both a grinder and flaker can be expensive, but some grinders have flakers built in.   If you have kids, you will find they love flaking their own oats and will thus be more interested in things like muesli and porridge instead of sugary cereals.

This is what I use:

It's a Schnitzer Vario.   It grinds and it flakes really well.  It has Corundum Stones which will last many years.  It not only looks beautiful as a kitchen appliance but works well too.   I throw various grains into it including wheat, spelt, rye, and other things like buckwheat, millet.  I can also throw spices in there like fennel seeds for a nice fine fennel flour to add great flavour to some of my breads.  And of course it will flake oats very nicely.   These come at a price but I believe you're making a life decision because you'll likely only ever buy and need one grain mill (unless you buy a cheap flimsy thing that doesn't last).

If you're wanting self-sufficiency then something with a manual feature will be needed as an electric mill is no good if the grid goes down !  The Country Mill grinder is well known and a big rugged metal affair with a big fly wheel.  Not something for the domestic kitchen imo but rather for a garage or shed with a sturdy bench that it can be nailed down onto.  Then if you're into "Heath Robinson" type gadgets you can hook a bicycle up to it if that's your thing !   Not for me I'm afraid.  So I went for the Schnitzer and bought a cheap sub £50 manual grinder for "just in case" scenario and will probably never use it.

Lots to consider.  I do hope you find something that suits.  Good luck.

ElPanadero's picture

Just to clarify, the stones in milling do not (or should not) ever touch each other.  The notion of two hard stones grinding against each other and "stone sand" pouring out of the funnel is typical but fantastical.  It doesn't happen.  There is always a gap between the stones and you obviously vary this gap to determine fineness of the flour.  It is the grains themselves that touch the stones and which must over a very very long time wear away tiny particles of stone.  The scale of this is minute though.  You will literally go through sacks and sacks of grains over many years before you ever come close to wanting to replace the stones.

sonika's picture

Thanks again!

Suza's picture

I am researching the purchase of yet, another, expensive kitchen tool - an electric grain mill.  My son has had a KOMO for several years and loves it.  I am recently retired and now have time to devote to baking, which I love to do.  We live in a rural area so the idea of having the freshest ingredients always at hand, prompted me to follow my son's lead. 

I became discouraged when, while comparing the differences between impact and "stone" mills, I ran across discussions about the safety of aluminum based corundum/ceramic grinding stones (as in the Komo).  After reading numerous comments and views, I've decided, no matter what method is used for grinding, there is going to be some "undesirable" element involved.  However, looking from a different perspective, by producing home ground flour (either stone or impact ground), at least we know what is going into our flour - something absent in the commercially ground flour from our grocery shelves.  I suppose one solution is to get a couple of rocks and grind away (LOL)

So, still undecided as to which type of mill to choose, I began looking at the inherent qualities of the flour produced by each.  I narrowed my choices down to the Wondermill and the Komo Classic.  After viewing a very good video comparing the two (as well as a hybrid manual/electric mill) at:

I have decided on the Komo. 

Judging by its great reviews, the Wondermill is obviously a good machine, but . . . . 1) the motor is made by LG and I have had a bad experience with LG kitchen appliances (a fridge and a dishwasher), and 2) it is made in Korea.  Never-the-less, I kept an open mind as the video showed the results each mill was capable of. 

Both quickly produced a very fine textured flour on the pastry/fine setting, but the Komo was capable of a cracked grain grind on the coarsest setting, while the Wondermill only produced a coarse bread flour at the coarsest setting.  This range of grinds, as well as the variable settings which can be adjusted as grinding is in progress, showed the Komo to be the choice for me.   I was amazed at how quickly the Komo ground, the ease of cleaning and its superior aesthetics (worthy of staying on the counter to enjoy every day).

They say a product is only as good as it's poorest ingredient.  I know there will be a learning curve, and failures (just as when I first began making bread), but I'm excited about embarking on this new adventure in my kitchen. 

And, of course, suggestions from experienced bakers will be appreciated!