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Help me design an Astrié Grain Mill !

jacques_spillmannjacques_spillmann OS Professional Posts: 48 PRO
edited January 17 in Community Support
Help needed!
I am a mechanical engineer with a problem, when I do something I want to do it right, with purpose and in the best way possible.
And the more I dig into a problem, or challenge, the more I discover things are not as simple as they seemed.
I've been making bread at home for about 10 years now but only recently (<2 years) started to make my own flour at home from wheat berries I buy at my local specialized store (in Los Angeles).
Milling wheat on demand is a game changer, making bread tastier and with more structure. Try to make bread from store bought flour that was milled weeks or months ago and results will be less than best, the dough won't rise as much and the taste will be weak.
And, that problem again, anything else than the best becomes unacceptable once you have tasted the potential for perfection (a simple baguette in a reputable Parisian boulangerie is one example of perfection).

The current milling setup I use today is far from ideal, it is slow, heats up the flour a bit and grinds the wheat berries like a coffee grinder would grind beans.
I have recently discover that there is a better to mill, that is closer to the ancient way of doing it, it's using stone (granite) mills rather than metal burrs and it treats the wheat with respect. There is a group of french grain milll makers in France (where I'm from originaly) that are re-inventing the milling process by mixing the traditional way with a modern approach to building the mill, resulting in a flour that offers the full nutritional potential of wheat.
I will not go too much in details for now about nutrition but to summarize: industrial flour = crap, artisanal flour = heaven (tuns of ressources about that online, enriched flour VS whole wheat flour VS stone mill flour).
So fine, everyone should know by now that whole wheat flour is better for you, and to get whole wheat flour you have to use the whole grain. But, when making bread, there is a key component of the grain we don't wish to use: the very outer layers of the bran (pericarpe layers). The bran in general constitute the outer shells of the grain protecting all the good nutrients, the bran is mostly fiber, which is not bad per say, but the very outer layers can cause 2 potential issues for our project:
  1. Interferes with the bread making process (limits the full development potential of the dough as it gets in the way of the gluten chains)
  2. Potentialy a bit harmful for the guts if you ingest too much (the very outer layer of the bran is not degistable by humans, can bind magnesium from your body, most likely to collect chemicals from the growing process)

Ok, now let's get the main purpose of this post:

After an extensive research, I came to the conclusion that most household grain mills do not properly process the wheat berries (not to mention most of them don't actually use natural stones), they don't really unrolled the grain which would lead to separating neatly the outer bran from the rest of the grain. Rather, they grind the grains and you end up with the whole bran in the flour. So fine, you can sift it, but then you're also probably sifting some good things at the same time that should stay in the flour (the inner layers of the bran, protein base aleurone, for example). So basically, sifting is ok but the goal is to sift as coarse as possible to maintain the nutritional qualities of the flour.
Learning about those french mill manufacturers and watching how they process wheat on their mills was a revelation, I finally understood why the bread at my local artisanal boulangerie I go to near my birth village in France is so much flufier and tastier than the one I make in LA. (I know, flour is only one parameter of the process but it's also kind of the most important one, so once I master this I can move on to the next thing that needs improvement). In a video of their bakery they mention they are using an Astrie mill, that made me curious and started this whole investigation.

I started to study the Astrie mill design and found out that it stems from the research and designs of, now famous in some circles, André Astrié.
You can buy an Astrie mill from one of the French manufacturers but they are made for bakers that process a lot of flours, their ouput is >100 lbs per hour, when for me at home I just need 5 lbs for my batch of weekly bread.
That led me to the conclusion that I have no choice but to design and make my own "miniature" Astrié mill so I can continue my quest to making the perfect French baguette at home, in LA.

Now that I’m out of that rabbit hole, I’m ready for action, here is why I need help:

  1. I’ll never finish the project by myself, I’m way too busy with my consulting business and home related activities (did I mention I was making bread 😝)
  2. I have some knowledge gaps when it comes to things spinning and choosing the right components for the job (bearings, motors, gears, etc.)
  3. I really want that perfect baguette 

I’ve already secured a pair of stone mills that I’m bringing back from France soon.

Here is a preliminary Onshape document with a basic assembly and some technical resources I’ve gathered from the Astrie design.

My first goal is a proof of concept, as low tech as possible, it could be a hand powered version, and then later, a more elaborate design that would include a motor, speed control, grain feeder and flour sifter.

Check it out and let me know if you can help, it’s on a voluntary basis for now, the design is made public as I want to share this with every home bread maker out there and allow everyone to source parts through their local market if they wish to build one for themselves, keeping the André Astrié philosophy alive.

With many thanks for your interest and for making it to the end of this long post!




  • dirk_van_der_vaartdirk_van_der_vaart Member Posts: 525 ✭✭✭
  • jacques_spillmannjacques_spillmann OS Professional Posts: 48 PRO
    edited February 14
    Thanks Dirk, i've done a lot of research on these household mills and none of them are treating the grains right! This is the very thing that actually inspired me to research more and came to the conclusion I needed to build my own!
  • Ste_WilsonSte_Wilson Member Posts: 195 EDU
    Interesting stuff!
  • dirk_van_der_vaartdirk_van_der_vaart Member Posts: 525 ✭✭✭
    @jacques_spillmann I am no expert on this but it seams to that the pattern on the granite stone,s, the pressure between the stone,s , the size of the stone,s and the speed and power of the electric motor are the thing,s to get right.
    In my opinion it best to start with a mock-up where you can easely adjust these thing,s and  when you are sure all the parameter,s are good then start with the design.
  • jacques_spillmannjacques_spillmann OS Professional Posts: 48 PRO
    absolutely, this is my first goal, get all those parameters right. Bear in mind though that there is already a lot of design parameters that were defined by the Astrie brothers as they spent several decades tinkering with the design of their mills... so I'm not starting from scratch. The only thing is to know if using smaller diameter stones (mine is 20cm - 8" instead of theirs which usualy are ~50 cm - 20") can reproduce similar results, in other words, is the Astrie design able to scale down. I know some manufacturers of Astrie mills have gone to a 30 cm - 12" but I wonder if it can be done with the 8" size. Speed is definetly an important parameter, which leads me to think that it might actually not work do to a manual crank version as we'll never reach the necessary speed. 
  • jacques_spillmannjacques_spillmann OS Professional Posts: 48 PRO
    Finally received the Millstones today, my next step is to finish the design of the first experiment and find out what speed settings are appropriate.
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