June 26, 2008 - 7:12pm
Nutrition of freshly ground grain
I would like to know how long it takes before freshly stone-ground grain starts to lose some of its wonderful nutrients. I'm assuming that the cooler temp of stone-grinding would allow the flour to maintain its vitamins and minerals longer than metal-milled.
SOL
The only people who talk about the nutrition value of freshly ground flour are people with a dog in the race. People who are selling mills, freshly ground flour or baked goods made with freshly ground flour. The web pages that promise good health and say, "all we changed was our bread" are inevitably pushing freshly ground flour or the equipment to make it.
Is it really better? I don't know because I haven't seen an independent study. I'd love to see some. Annecdotal evidence IS important, it is persuasive, but it isn't proof. All too often you find that someone who had health issues changes a lot of things at once and doesn't think about them. The one that took a lot of time was grinding the flour and baking the bread, so that's what they focus on. I'd like to see chemical analyses of the flour when it's freshly ground and again every day or two for a month, and every week or two for a few years. Or even with less frequency, but still offering some degree of history to the same flour. And then I'd like to see some sort of study as to what impact that would have on people.
My take on the matter? From what I hear somewhere between 120 and 140F is the critical temp. You don't want to go past that. And neither my micronizer mills nor my KitchenAid mill raise the temps too far.
The only thing I know of that decomposes is the fatty acids in whole grain flours which will go rancid. Rancidity is distatesful but it is not a short term health risk, though some people point out the oils are oxidised and could speed oxidation in your system. Still, if you're hungry you can eat goods made with the rancid flour without becoming ill. It won't be appetizing though. How long does a whole grain flour last? It depends on storage conditions, but 6 months to a year at room temperature, if memory serves.
The breadmaking characteristics are another interesting matter. Many people like to make bread with freshly ground flour, flour "still wriggling with life" as Alan Scott put it. And it works pretty well. However a few days later, that flour can be very hard to use - the dough is so elastic it is very hard to work with from all reports I've heard. At that point, letting the flour age a few weeks will restore it's baking characteristics.
Hope that helps,
Mike