The Fresh Loaf

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Flour Milling Lab Results

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proth5's picture
proth5

Flour Milling Lab Results

I am creating a new blog entry to discuss bwraith’s flour test results just to move it up as his original entry was getting old.  I admit we’re going overboard on this, but I find it all very interesting (no pictures- just discussion of flour test results) – so be warned!

Letters in my responses correspond to letters on bwraith’s test results.

I don’t know how to do that “quote thing” so I’ll just put bwraith’s original words in quotes when I want to respond to something directly.

Also, these are just my humble speculations.  If anyone has a more complete knowledge, I would be most grateful to hear their interpretation of the results that were so graciously provided.

Bill,

As you said…”One main thing that was unexpected for me, was that the lowest ash white flour coming out of the second pass had high protein and wet gluten content, yet it did not have great mixing qualities in the farinograph (low mixing tolerance). My theory is that the first grinding pass may result in some very high protein dust particles being released through the 80 mesh sieve. Maybe that extra protein in the flour out of the first pass is needed for good gluten formation and is proportionately too low in the flour from the second pass. I've been reading that some of the different types of protein vary in size and whether they adhere to the starch granules or not. I guess there are milling operations that use air separation to separate the different sized protein particles and then blends them in various flours to create desired protein specifications.”

What intrigues me is that I am told that the outside of the endosperm is whiter (lower in ash) than the inside of the endosperm and although the protein/gluten is higher it is of lesser quality.  If P2a was producing flour from the outside of the endosperm, this would be consistent with your result of lower tolerance.  What you are getting as flour on P1 would be acting as a balance against the P2a result when blended for baking.I don’t think your process is reducing protein quality – I think that your process may be delivering different parts of the endosperm at different points in the process.Also, if you look at the Seguchi paper that I cite in my other blog post, it may be that the flour was aged insufficiently to see the full potential of its protein.  He is looking at aging periods in excess of 100 days to achieve full potential.

What also intrigues me is that the results for P1 tracked so closely to whole wheat flour.  I frankly would have expected those results to be more like the Golden Buffalo.Nice to know that the multi-pass milling created flour with lower starch damage than commercial flour.  I have seen some discussion that some home milled flours seem to be “thirsty.”  This would be indicative of a kind of starch damage that you did not experience.

Finally – when all is said and done, the values for both of the flours are within those considered acceptable for commercial baking – not necessarily ideal values, but well within tolerances.  This is borne out by the bread that you produce. So, no need to age to maximum potential to get good bread.I know, I need to get enough flour milled to get some tests on my stuff.  I’ll do it – I really will.  I have some other things to attend to in the short term, but I know I’ll do it.  In the meantime –

Happy Milling!

Pat 

Comments

bwraith's picture
bwraith

Pat,

I'm subscribed to your blog and have been reading along. Unfortunately, I don't have a whole lot to add at this point.

Do you have a source that describes the starch, protein, and ash distribution in the inner and outer endosperm? I've read only cursory discussions in various texts and papers, and I had somehow come to the impression that the innermost endosperm was lower in ash content than the outer endosperm, same with the protein content, so some of what you're saying about ash and protein content in the inner and outer endosperm above is different from what I thought.

I have also read about differences in the type/quality of protein in the inner vs. outer endosperm.

I think one reason there is higher ash content in the P1 flour may well be because there is some pulverized bran from the first pass falling into that first batch of flour, and that may increase the ash content of the flour coming through the 80m sieve in the first pass.

I probably should try to make some bread with that P2a flour. It might be just fine. I tend to undermix and use folding to develop the gluten during bulk fermentation. Mixing tolerance may not be such an important characteristic in that case, anyway. The low mixing tolerance has me wondering if it the dough made from P2a flour might fall apart in the acids from the sourdough fermentation, though.

I'm going to try doing the same basic set of milling and testing tomorrow on some Wheat MT Bronze Chief berries I've been tempering. Hopefully, I'll have some lab results later in the week or early next week, if all goes well.

The bread inventory in my freezer is reaching an all-time low, which is good in some ways. Still, I'll soon have to abandon this lab phase and start baking bread again with my flour instead of sending it to the lab, as interesting as this milling, sifting, and testing has been.

Bill

 

proth5's picture
proth5

Bill,

If you look at the book "Bread, A Bakers's Book..." starting on page 34 there is a good overview on wheat and milling's effects on it.  Also starting on page 363 is a good overview on Rheological testing on flour.  I find those to be good quick references. 

Ummm.  I got confused on the ash content - you are right on that - but I re-checked and I  got protein quality correct - it is higher towards the outside, but of lower quality for bread.

It seems like either one of the flours would be ok for bread.  Let me know if you bake some up.

Looking forward to your future test results.  I've got about 2 pounds of white wheat tempering with my unscientific method and hope to mill today. This time I will age half of the flour for 2 months - so results to follow - slowly.  I'm saving up in my "over the top hobby fund" for a moisture meter.  I decided that if I'm going to get one - I might as well get the good one.

It probably is time to get back to baking.  After all, that was the original goal, no?

Pat

bwraith's picture
bwraith

Pat,

I go back to Hamelman's book frequently. It is just an excellent reference.

Soon enough, I'll get back into some real baking here. I just finished a new milling/sifting session with Wheat MT Bronze Chief berries (hard red spring wheat). The process went much the same as with the HRW wheat from Heartland Mill. However, not surprisingly, it seemed like the process required somewhat finer mill settings to achieve about the same breakout of product in each sieve. I've sent off another bunch of samples to the lab and also sent in some interesting commercial flours for testing to have comparisons again, as before.

I also am beginning to understand that there is probably a threshold effect in the coarseness setting of the mill. In other words, over a very small variation in the mill coarseness setting that seems to be right around 1/6 to 1/8 turn open (from the setting of the mill screw where the stones begin to touch), the yield goes from heavily favoring larger than a #40 sieve to heavily favoring smaller than a #40 sieve. In the same vein, I get very little difference in yields or texture whether I set the mill 1/16 open or as close as it can go without touching. I'm not quite sure what to do with this knowledge. The main thing is that I've realized there is some benefit to using the 26 and 40 mesh screens on the first pass and then switch to 40 and 60 for the second pass - always using the 80 mesh screen for separating out flour.

Bill

proth5's picture
proth5

Bill, 

Looking forward to more test results.

As my favorite teacher would tell me - "Then you'll just have to try grinding a batch of flour using each method and see which one you like better when you bake" - Oh, yes, I can almost hear his voice now...

My process really varies from yours on how I sift, since I use one screen at a time.  But what benefit do you you see for using finer screens on the second pass? I wonder from time to time, if I shouldn't get a coarser seive for my first two passes and remill only the stuff in the coarser seive. This would reduce the effort tat goes in to the process - which is something serious for me to consider.

What I find to be "fun" is how fluffy the grain gets after the first couple of rough passes.

It is quite a project for me to mill enough to send for analytics - but I feel that I will need to gear up in the near future to do it.

Flour is quietly aging...

Pat

bwraith's picture
bwraith

Pat,

What I've noticed is that on the first pass, when I set the mill to 1/6 turn open, which is a fairly coarse setting (about 1/4 of a grain thickness separation between the stones), I get, very roughly speaking, 4 products. The first product is flakey bran. Then, there is a reddish granular product. Then, a whitish granular product. Finally, there is flour, which is more or less a cream color. If the mill coarseness setting is "right", then the 26m sieve will catch only the bran, the 40m sieve will catch the reddish granular product, the 80m sieve will catch whitish granular product, and finally through the 80m sieve you get the cream flour.

On the next passes through the mill, the setting is much finer. The product is almost all smaller than the 26m sieve, first of all because if the bran is "pure enough", meaning it's all just flakey bran with no red or white granules mixed in, then I would just reserve it. Also, in any event, very little product greater than 40m is still greater than 40m after passing through the mill at a fine setting (like 1/24 or 1/32 turn open, i.e. almost touching). So, it doesn't really help to use the coarsest sieve, since everything will go throug it, and just about all will go through the 40m sieve on all the subsequent passes. This was true even with a second pass at 1/16 turn open, which I tried at one point.

So, I have been moving to finer sieves for the second and all subsequent passes, simply to have some separation of product. The separation seems to be between a somewhat finer granular reddish product than above, a somewhat finer whitish granular product, and more flour. No matter which of the products above are re-milled, you get some of each of these products. The flour coming from remilling and resifting of whitish coarse granular product tends to be almost white. The flour coming from the reddish coarse granular remilled product tends to be creamy or even golden. Typically, the finer whitish granular product is separated at around the 50-70 sieve range, and the finer redish granular product is separated around the 35-50 sieve range.

So, I'm separating out 2 or 3 grades of flour from off-white, to creamy/grey, to golden. The ash content of the off-white flour is less than .9%, the ash content of the creamy/grey flour is from around .9% to 1.1% ash content, and the golden flour is upward of 1.2% ash content. The off-white product comes from re-milling the whitish granular product in the 50-70 sieve range. The creamy flour comes mostly from re-milling the reddish granular product and from the flour that comes out in the first pass through the mill. The golden flour is product that comes out later, after 3 or more passes, when what's left to re-mill is mostly reddish or at least darker fine granular product.

If I were only trying to separate out one grade of creamy flour, it would probably be easier to do a finer setting to begin with and then use only one or two siftings and remillings with most of the product. I don't know if I will care about multiple grades of flour after all this, but the idea was that I could then customize my flour from a fairly white flour to a very high extraction, nearly whole wheat flour, depending on the type of bread I want. However, I have to admit that I've found myself mostly making breads that work well with cream to golden flour, which would make the extra steps I'm going through to separate out the off-white flour unnecessary.

The other thing I have in mind is trying out some interesting new recipes that revolve around taking the various products and handling them differently before recombining them to make a whole grain bread. For example, I could picture lightly simmering the bran and letting it soak, making a mash out of a finely ground flour re-milled from the reddish granular product, and just soaking the off-white flour for a shorter time, and making a levain from the whole spelt, rye, and some of the cream flour, then recombining them in the final dough.

Bill

proth5's picture
proth5

Bill, 

Thanks for the details.  Gives me something to think about in terms of my process.

I like your idea of treating different outputs from the milling process in different ways within a single loaf.

Just right now I am up to my eyeballs in non-milling and non-baking related matters, but I am looking forward to your next set of test results.  In the meantime, I just baked a loaf from fresh milled and since it was mostly a carbon copy of my first one (let no one say I haven't reached consistency in my bread output...) I didn't bother with pictures.  And so, I have enough flour to age for 2 months to do a controlled experiment on that.

Happy Milling!

Pat

bwraith's picture
bwraith

Pat,

I've posted an update to my blog entry about lab results and wanted to let you know. I still don't have the final test results from CII, so there aren't any farinograph results. Hopefully, I'll be able to post those on Monday or Tuesday if they get back to me by then. There are several additional commercial flours I tested, so it will be interesting not just for the home milling results, but also to see some comparisons with some relevant purchased flours.

Bill

proth5's picture
proth5

I  will take a look! - May be a while before I really get to anything, but will check back later next week.

Pat