The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Soy Flour - Shelf life?

RichmondJim's picture

Soy Flour - Shelf life?

I found an opened bag of soy flour in the back of a cabinet sealed in a zip-lock bag. I have no idea how old it is, nor why I purchased it in the first place ;-). Do you think it's still good and if so, what can I do with it?

subfuscpersona's picture

Here are two easy ways to test of the soy flour is still sufficiently fresh...

> smell it - if good, it should smell either faintly "beany" OR have no smell at all

> taste it - put a pinch or two on your tongue and let it dissolve. Fresh soy flour has a faintly sweet taste. Older (but still good) soy flour may have no taste at all. If the taste is bitter or otherwise "off", I wouldn't use it.

If you judge your soy bean flour to be OK, please do immediately refrigerate or freeze it so it won't degrade further.

==== more on soy flour ====

FYI, I have used soy flour in baked goods off and on for about 25 years. However, as a home miller, I always milled my own soy flour from organic soy beans. I have, once or twice, purchased a one-lb bag of Bob's Red Mill organic soy flour but that's the extent of my experience with purchased soy flour. I always either refrigerate or (preferably) freeze soy bean flour; I never store it in a kitchen cupboard.

You don't mention if your soy flour is full-fat or defatted. You also don't mention if it is organic or not. (I hope it is organic, though a high percentage of the soy beans grown in the USA are GMO - that is, from genetically modified seed). If it is not organic, I would throw it out regardless of taste. I once purchased some soy beans that were not organic and these beans did not make a good flour.

If the soy flour is full fat (it should say whether it is full fat or defatted soy flour somewhere on the bag), it will degrade fairly quickly if not refrigerated or frozen. The soy bean naturally has a fair amount of oil (easily observed if one makes soy milk from whole soy beans, which I also do) and flour milled from it will go rancid fairly quickly if it is stored at room temperature (my estimate is in about 1 -2 months, depending on it's exposure to warmth). Defatted soy bean flour has a longer shelf life, but, since I normally home mill my own soy bean flour, my soy flour is always full fat, so I really have little experience with defatted soy bean flour.

Hope this helps some. Feel free to post back if you have further questions or concerns. If you find that your soy flour is OK, I will be happy to give you some suggestions on use (not all of which will involve bread) - SF


nicodvb's picture

Please, can you describe the effects that soy flour has on bread? Does it make it raise higher or make it feel more gummy? does it whiten the crumb?

Soy flour contains protease inhibitors and as such it should have a serious impact on the volume and on the consistence of the crumb. The bleaching effect should be due to other enzymes.


rayel's picture

It makes it higher, conditions and ripens the dough faster, in small amts, like 1 Tablespoon  per 2 loaf recipe, using 2 lbs. wheat flour. Larger quantities of soy flour,requires special handling, to keep it from binding up the gluten. I read it has a bleaching effect on flour as well, even at that small amt. Soy milk creates a light colored crumb (same enzyme?) in whole wheat breads. It needs to be really fresh, or boil first.