What is “Ash Content”?

In the same way that Americans speak of flours in terms of their protein (gluten) content, Europeans speak of ash content. But what is this mysterious “ash” and why would you want it in your flour? The answer is that the ash isn’t in the flour, it what’s left over after a set quantity of flour (100 grams, I think) is burned — burned in such a way that the starch burns up almost entirely. What’s left are mostly minerals.

So what does this minerally “ash” tell you? More than you’d think. If you consider a wheat berry in the same way you would an onion: a thing made up of many layers. The layers on the outside are the tougher ones that contain less of the starch than the much purer inner layers.

The outermost layer is the shell of the wheat berry: the bran. It doesn’t have much digestible starch in it, but rather hard cellulose and other tough stuff. When all that burns up you get quite a lot of leftover “minerals”. The outer oily germ also contains very little starch, and so leaves more minerals behind when it’s burned. And indeed the outer layers of the starchy endosperm contain more non-starch matter than the innermost layers.

So you can see a pattern developing here, I think. Flours with higher “ash contents” are those that have more of their non-starch bits left in them when they hit the fire: bran, germ and such. So a high ash content (say, 1.4%) is going to be a whole grain flour, one that includes the bran, germ and outer endosperm layers, and a low ash content (0.3 percent or less) is going to be a cake flour, that includes only the inner endosperm.

So what else do you know if you know the ash content percentage? Well you know how coarse or fine the flour is since the outer regions of the wheat berry are tougher adn the inner ones softer. You also know the protein level more or less. Why? Because most of the protein in a wheat berry is in the outer layers of endosperm. So a higher ash content flour, in addition to having more bran and germ pieces in it, will also tend to have more protein (gluten). Here you start to see where ash contents begin to overlap to some degree with North American “extraction rates” and gluten percentages. They’re all ways of judging a flour’s relative texture and strength.

15 thoughts on “What is “Ash Content”?”

  1. Again, fabulous information in a completely accessible format.

    I’m confused about this, tho, Joe: if the higher extraction or ash flour has more of the gluten proteins, why is it more challenging to get a nice rise from?

    Meanwhile, you totally HAVE TO write a book. You are as authoritative as McGee and at least 14 times more readable (no offense to McGee; I respect him but just can’t actually stay with him for more than about 3 minutes).

    1. No books! I’ve got a mortgage to pay! 😉

      But thanks, Rainey! To answer your question, the reason high extraction flours create such dense breads is because of the bran that’s in them. Bran pieces are brittle shards that slice through gluten networks as they form. The oil from the germ also doesn’t help…it coats the ends of the gluten molecules, keeping them from bonding to one another.

      To get a high gluten baking flour you need to start with a hard wheat, one that has more protein all through the endosperm (even though the outer layers will always be richer in proteins), then use more of the inner layers that are free of bran. Make sense?

      – Joe

      1. I get the portion about cutting the strands and I can see that a higher oil content could interfere with the attachment necessary to create a structure. Are you saying, about the rest of the protein in the denser outer layer, that it’s there but just not as available?

        Re the book, you’re already writing it, babe! All you need is an editor. ;>

  2. I just got a whole wheat flour with 12.5% protein & 0.49% Ash.
    This seems like a pretty low Ash for whole wheat. Can you tell anything about this flour from these numbers?

    1. Hi Margie!

      Sorry for the long wait. That’s very interesting. I wonder if the flour you have is one of the newer “white wheat” flours. Those flours are milled from hard white wheat (instead of hard red wheat) and as a result have a lot of protein. I don’t know anything about the bran and germ of hard white wheat. I could be that it produces a lower ash content as well. That’s all I can think of!

      Sorry again for the late reply!

      – Joe

    2. ash is the mineral content which was there in the product example cake or muffins, bread, etc….
      guys you see it might be the flours which consists of more mineral content such as oats with bran 485% etc. etc.. but i hope ill never visit this site again since i was closing it ok va..

      1. Daniela et al.,(2013) studied the influence of baking conditions on muffins’ quality. Surface crust color was monitored during baking tests at oven temperatures ranging from 140 to 220 °C, and browning kinetics was modeled by means of a browning index, BI, which follows a logistic model a joint analysis of core temperature profile and BI curve can assist in the prediction of baking time. Finally, weight loss, crust/crumb ratio, crumb and crust moisture content, porosity, crumb and global densities, and texture were measured in the already baked muffin. The water content in the crumb remains almost constant, while considerable dehydration occurs in the crust. Finally, the results showed that intermediate oven temperatures led to a more porous, aerated, and soft crumb, with intermediate textural properties.

        1. Thanks, Petri. Seems like you know what you’re talking about. Don’t let me get in the way!

          – Joe

  3. hi joe its me again like crucible, pertri dish, weighing balance, muffle furnace, hot air oven, im the whipper i the cake batter and bread dough, im like the muffle furnace at 650 dc for over night, im like the hot air oven at 100 dc for 5 hours, im the 5g of sample in the crucible and 2 g of sample in the petridish,,im the chopped potato kept in the drier, and the steam in the boiler

    1. Ash Content
      Ash content was determined using the method of. About 5 g of each sample was weighed into crucibles in duplicate, and then the sample was incinerated in a muffle furnace at 550°C until a light grey ash was observed and a constant weight obtained. The sample was cooled in the desiccator to avoid absorption of moisture and weighed to obtain ash content.

      Quality Evaluation of Composite Bread Produced from Wheat, Maize and Orange Fleshed Sweet Potato Flours
      Igbabul Bibiana1, 2, , Num Grace2, Amove Julius2
      1Department of Food Science and Technology, University of Uyo, Uyo Nigeria
      2Department of Food Science and Technology, University of Agriculture, Makurdi Nigeria
      American journal of food science and technology

      Igbabul Bibiana, Num Grace, Amove Julius
      American Journal of Food Science and Technology. 2014, 2(4), 109-115

      Igbabul. B., Nun. G., Amove. J (2014) “Quality Evaluation of Composite Bread Produced from Wheat, Maize and Orange Fleshed Sweet Potato Flours” American Journal of Food Science and Technology 2(4), 109-115

      Ash was determined by igniting the samples on a hot plate by heating till smoke formation ceased. it was then in a muffle furnace at 650˚c for 6 to 8 hours. The weight was recorded after cooling. The difference in weight gives the estimation of ash content (Anusooya et al., 2011).
      muffin sample crumbled from the interior crumb of the muffin were accurately weighed in petri dishes. it was dried at 100˚c for 1 hour and then cooled in a desiccator and then weighed. samples were dried again and reweighed till concordant weight was obtained. percent moisture contents of muffin sample was determined (S. Sivam et al., 2011).

  4. 9.2 ASH CONTENT
    The ash content for the control muffins were 1.85% andof the muffin has increased significantly with the use of soya, maida, ragi, maize with other ingredients, wheras with maida, corn, oats, ragi flour blend showed lower ash content of about 1.52% with butter, sugar, cocoa powder, milk, baking powder, and the muffins with oats flour blend showed lower ash content.
    The ash content for the control muffins were 1.

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