Potato Flour

One US cup of potato flour weighs between 160 and 184 grams (5.6 to 6.5 ounces), depending on how the cup is filled and which source measured it. That range is the answer; a single number would not be. Every figure behind it is below, with the method each source used.

Also called whole potato flour, dehydrated potato flour, potato flour gluten free, Bob's Red Mill potato flour.

Potato flour weighs 160 to 184 g per US cup (5.6 to 6.5 oz). USDA lists a cup at 160 g, Ener-G's label works out to 168 g, while Bob's Red Mill labels a quarter cup at 45 g (180 g per cup) and King Arthur gives 184 g. The two groups disagree by more than the 10% tolerance, so this entry publishes the range.

Potato flour is whole potatoes, peeled, cooked, dried and ground: Bob's Red Mill describes its flour as ground from whole peeled and dehydrated russet potatoes. USDA puts it at 6.5% water and 83% carbohydrate, mostly starch, with 7% protein and 6% fibre. It is not potato starch, which is the pure starch washed out of raw potatoes and behaves very differently: potato flour absorbs a lot of water and tastes of potato, and bakers use a few tablespoons of it in bread and rolls for a soft, moist crumb. Potato starch has its own entry on this site.

USDA SR Legacy "Potato flour" (FDC 168446) gives one portion, 1 cup at 160 g. Ener-G's pure potato flour labels a quarter cup at 42 g, 168 g per cup. Bob's Red Mill, the most common US brand, labels a quarter cup at 45 g on every current bag and lists 180 g per cup in its own flour weight chart; an older Bob's label gave 3 tablespoons at 34 g, the same density. 45 g is not the 30 g reference serving that flour labels usually print, so Bob's figure looks like a weighing of its own flour. King Arthur's chart lists potato flour at 1/4 cup = 46 g, 184 g per cup, within 2% of Bob's.

Rose Levy Beranbaum's bread book, as quoted by bakers online, gives 5 tablespoons of potato flour at 51.5 g, about 165 g per cup, which sits with USDA.

The physical check explains a 15% spread without anyone being wrong. Potato flour is a fine, heavy powder, much denser than wheat flour, whose cup is about 120 g. How fine it is ground and how it settles change the cup: Bob's sells its product as super-fine, and very fine flours pack tighter when spooned. A cup that has settled in the bag, or that has been scooped rather than spooned, lands at the heavy end; a loosely spooned cup of a coarser grind at USDA's 160 g. King Arthur's figure agrees with Bob's, so it is not a correction here.

Practical guidance: weigh potato flour, especially because recipes use so little of it that a spoonful either way changes the dough. If you only have spoons, a tablespoon is about 10-11.5 g: 2 tablespoons for a loaf of sandwich bread is 20-23 g. A 24-oz bag of Bob's holds 680 g, about 3 3/4 cups at their figure. Do not swap potato flour and potato starch one for one; they are different ingredients.