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Is it okay to measure flour by weight by converting from volume?

The choice of measuring by volume and weight is discussed. I've always preferred weight, but have a lingering feeling of an additional error that is more prevalent when measuring by weight, namely any amount of moisture content in the flour.

Say, perfectly dry flour has a certain density d.

The flour that has a "maximum moisture content", have certain percentage flour, and a new density d_2. These two numbers conspire to change both the volume and weight measurments.

"Maximum moisture content" means "not obvious", I guess.

Are there any known results of this kind? How much more/less moisture may exist in the flour without being noticable?

To further complicate matters, I guess it also means that any added water should take that extra moisture into account?

I'm thinking of the similar discussion of mushrooms; weight vs volume, which always claims weight is better - to which I disagree; just think of dried mushrooms, at a fraction of the initial weight. Of course a powder isn't the same as a mushroom with cell walls, but I guess as single flour particle could absorb moisture anyway?

  • I'm having a hard time figuring out what your question actually is @NiklasJ. Are you asking how much moisture is typically present in flour? Or how much water flour may absorb over time? It's just not clear.
    – GdD
    Jan 29, 2018 at 13:33
  • I don't have any citations to give so I'm not making this an answer, but I would assume that the variation in the weight of flour through moisture content, below a level where flour would appear damp and you would probably opt not to use it,would be minimal. I certainly can't imagine that the variation would be greater than the margin of accuracy of most kitchen scales for domestic baking amounts.
    – Spagirl
    Jan 29, 2018 at 13:36
  • @GdD I've updated the question, perhaps clearer now?
    – NiklasJ
    Jan 29, 2018 at 13:47
  • You could test the hypothesis yourself by weighing out two equal quantities of flour and placing one in the oven for 4 or 5 hours at about 103° C. Then weigh the oven-dried sample again and see if it is significantly lighter. (that is broadly the method used by The American Association of Cereal Chemists, apparently. archive.org/stream/cu31924003565326/cu31924003565326_djvu.txt my own guess is that domestic kitchen scales are unlikely to be sensitive enough to detect a difference.
    – Spagirl
    Jan 29, 2018 at 13:53
  • So you're asking whether absorbed moisture changes weight or volume measurements more?
    – GdD
    Jan 29, 2018 at 13:53

2 Answers 2


Here is a post on the subject I found interesting. http://www.genuineideas.com/ArticlesIndex/flour.html

The findings may not be definitive, but seem logical enough to be at least close. Basically, my paraphrasing, they find the difference between completely dry flour and very humid conditions for most of us to be real but much less than that from volume measure. They get more technical on some of their justifications than some might prefer, but generally claim that weight should not vary by more than 3% for most of us, and that given most home scales are accurate to about 1% and we classify that as precise measuring, 3% is not huge.

Guessing here, but I would suggest that other ingredients may also be effected at least in this same range by humidity and this effect is less than altitude variations, and that volume measures are likely effected by humidity which would allow increases in compaction as much, maybe ore than weight. Given 3% as a rough guide, I think this fits into feel and experience areas and normal variations in cooking. For those outside the "normal" band, desert and high humidity coastal type areas, having lived in both, yes, it is one more curse of trying to get consistent results there.

  • Interesting post. I noticed this when making pizza dough. I've had very consistent results before but now they usually turns out too dry. Perhaps the thin dough amplifies the difference.
    – NiklasJ
    Jan 29, 2018 at 14:30

Having lived in Arizona (VERY low moisture - often 3-5 %, I was born there) and now in the Philippines (High 90s humidity always), the difference is VERY small, not usually noticeable. It is within "normal tolerances". Each brand can be a little different too, but most are nearly the same.

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