Discovering Chestnut Flour
As if on cue, the arrival of the Fall Equinox brought with it that crisp scent of morning air… and the beginnings of incredibly tempting magazine recipes for all things autumn. While butternut squash, predictably, leaves other ingredients in the dust as far as its frequency of mention, I’m seeing more and more mention of chestnuts as an accompanying flavor to everything from pastas and meats to desserts.
Since good, quality fresh chestnuts are still a little ways away (but be assured: once they arrive, you’ll hear about it from me first), I decided to whet our collective appetite for their delightful, sweet and nutty flavor by giving chestnut flour some airtime.
I’ve already encountered chestnut flour this year on my fabulous gluten-free honeymoon to the South of France, where one vendor at a village festival was selling fresh crepes made from farine de châtaignes (chestnut flour), filled with an obscenely decadent chestnut creme (think Nutella, but made with chestnuts and honey) or your choice of typical crepe fillings. I particularly appreciated this authentic version of the sweet crepe; after all, French cuisine offers us a wonderful gluten-free savory crepe option in its buckwheat crepes (called Crêpes de Sarrasin), but most sweet crepes are still made with plain old wheat flour.
But we patisserie-deprived gluten-eschewers can now have our crepes, and eat our Madeleines, too. The wonderful people at Dowd & Rogers offer a long list of chestnut flour gluten-free recipes on their website, including this one for Chestnut Flour Crepes and this one for Chestnut Flour Madeleines. (I cannot tell you how long I’ve been looking for a gluten-free madeline recipe! Substitute the milk and/or egg replacement of your choice to modify these recipes for your dietary restrictions.) In true French fashion, the latter recipe uses a full stick of butter, which translates into about 1.3 tsp of butter per Madeline. Health food it is not, but my philosophy is that having to break out the madeleine pan, preheat the oven and wait for 20 minutes every time we want to indulge in a little bit of cakey naughtiness is a very good way to prevent the impulse binge. Bake them, enjoy them, share them, and that’s the end of it.
Given how rarely we come across chestnut flour, you may be as surprised to learn, as I was, that it was a traditional substitute for wheat flour in Italy during the middle ages, and was used extensively for making bread and pasta. Sadly for us, most pasta, gnocchi and bread recipes that call for chestnut flour (Farina di Castagne) combine it with wheat flour. If you can eat gluten, you can try substituting up to 1/4 of the all-purpose (white) flour in your baked goods/pasta recipes with chestnut flour, or in recipes that call for some cake flour in addition to the all-purpose flour, try substituting all of the cake flour with chestnut flour. If you’re baking gluten-free, you can try substituting part or all of the white rice flour in a recipe with chestnut flour. To be sure, it’s an expensive swap, but as you’ll see below, it’s a glycemic-ly advantageous one if you can afford it.
All About Chestnut Flour
While Chestnuts are technically tree nuts (and therefore people with tree nut allergies should take care… you may or may not have a reaction to chestnuts!), Chestnut Flour is quite different than the flours/meals of other tree nuts, such as Almond Flour or Hazelnut Flour. To start, chestnut flour is very low in fat; in fact, chestnuts have a starchy profile that makes their flour more similar to typical grain flours in its nutritional (and functional) profile than the typical nut flour. By way of comparison,
- 1/4 cup almond flour contains 160 calories, with 6g carbohydrate, of which3g are fiber, 6g is protein and 14g is fat
- 1/4 cup of chestnut flour contains ~95 calories, with 21g carbohydrate, of which <1g is fiber, 1g protein, 1g fat*
- 1/4 cup all-purpose white (wheat) flour contains ~114 calories, with 24g carbohydrate, of which <1 is fiber, 3g protein, <1g fat
* Note: if you come across the Dowd & Rogers brand, there is clearly a typo on their nutrition facts label–one which I have emailed them about. A 1/4 cup serving does NOT miraculously contain only 25 calories.
While chestnut flour is still considered a high glycemic index food (the source I consulted rated it a ~65 on the index; a food must be 50-55 or lower to be considered ‘low’), it is still considerably lower on the GI scale than typical flours used for baking, glutinous and gluten-free alike, such as white rice flour (GI=~95), potato starch (GI=~95), Arrowroot starch (GI=~85) and white (wheat) flour (GI=~85)**. To be sure, it’s considerably more expensive (and hard to find), but for those of you looking for lower GI, GF substitutes for the white rice flour in your recipes, chestnut flour could be a good option… so long as you’re not allergic to tree nuts, that is.
If you’re not sure what all of this means, a sidenote: the GI, in a nutshell, is an index that compares the blood sugar response a food produces compared to the response created by pure glucose (sugar), which equals 100 on the index. A food with a high GI (say, 95) essentially produces the same spike in blood sugar levels as eating pure sugar. Generally speaking, in the flour world, the lowest GI flours will always be those that are higher in protein and/or fiber, such as quinoa flour, chickpea flour, whole wheat flour, rye flour, teff flour and buckwheat flour. Research has shown that diets with an overall lower-glycemic effect (mostly diets rich in whole grains, beans and vegetables as opposed to diets high in refined grains and sugar) are linked to a variety of positive health outcomes, particularly a lower risk of developing diabetes and cardiovascular disease. Since so many of the most commonly-used gluten-free flours are so darn starchy, it’s good to be aware of your lower GI options and choose them whenever possible.
** Just another note on the numbers: GI values will vary–sometimes widely– depending on the method used to measure them (such as whether the researcher compared the food to glucose or white bread), and the particular samples of food products analyzed. GI data should be used directionally–as in, to compare the relative effect of one food to a similar food–rather than as absolute numbers set in stone. To complicate matters, a food’s ACTUAL effect on your blood sugar will be influenced by how much of it you’re eating and whatever else you’re eating it with… assuming you’re not going to be eating plain chestnut flour as a snack. This is the idea behind a concept called the glycemic load, which is what you *really* care about.
If you are going to be partaking in a high-GI indulgence, it’s better for your blood sugar to eat it AFTER a meal that contained some fat, protein and fiber so that the latter nutrients will blunt the glycemic effect of the food. In other words, eating a cupcake on its own as an afternoon snack will produce a higher blood sugar spike than eating that same cupcake after a sensibly balanced meal. And of course, taking a nice brisk walk after the snack or the meal will also help dampen the glycemic effect of whatever you’ve eaten.