Flour from two small mills, and what it changed in the loaf

For three years I bought whatever rye flour the supermarket had and quietly assumed that flour was flour. Then a market stall sold me whole rye ground four days earlier, and the next loaf behaved like a different recipe.

Baked: 23 November 2025
Written up: 15 March 2026
Reading: 8 minutes
Kitchen: Frankfurt am Main

Stage 01Weigh out

What the type number actually tells you

German flour carries a type number, and that number is a measurement of ash: how many milligrams of mineral remain when a hundred grams of the flour is burned. More bran means more mineral, so a higher number means a darker, more fully extracted flour. Rye 997 is the common light-to-medium one, 1150 is darker, 1370 darker still, and whole rye carries no number at all because nothing has been taken out of it. The figure says nothing about protein, freshness, grind, or how the flour will behave in a bowl.

Understanding that stopped me reading the number as a quality ranking. An 1150 from one mill and an 1150 from another can absorb noticeably different amounts of water, because the ash figure describes neither how finely the bran was ground nor how long the flour has rested since milling. The mill, the type and the milling month now go on the side of the storage tub in pencil, because when a loaf comes out wrong the flour is the variable I am most likely to have forgotten about.

Stage 02Work it

Whole rye that was ground last week

There are small mills north of the city, out where the land flattens into the cereal fields of the Wetterau, and a couple more tucked into the Taunus valleys on the other side. Some of them bring flour down to the weekend markets in paper sacks with the milling date written on by hand. Flour a week old smells of grain rather than of paper. It also ferments faster, sometimes markedly faster, because the enzymes in fresh rye are more active and have had less time on a warehouse shelf to quieten down.

The first sour I built with fresh whole rye was ready in eleven hours instead of the sixteen written on my card, and because I did not go and look at it, it was well past ripe by the time I mixed. The loaf came out sharp, sticky and low. Fresh flour does not need a different recipe so much as a different schedule and an earlier look at the bowl. Whenever a sack is new I check the sour at the eight-hour mark now, rather than trusting a number I wrote down in a different season.

Stage 03Watch it

Water, and the twenty minutes I now wait

Rye absorbs water slowly compared with wheat, and coarse, freshly ground rye absorbs it more slowly still, which makes judging hydration at the mixer unreliable. A dough that looks exactly right the moment the machine stops will often be stiff and dry a quarter of an hour later, once the bran has taken up everything it wants. For a long time I corrected at the wrong end of that process, adding flour to a dough that felt too wet and finishing with bricks I had no explanation for.

The fix turned out to be patience rather than arithmetic. Mix to a rough dough, cover the bowl, wait twenty minutes, and judge the hydration then; if it wants another twenty or thirty grams of water at that point it takes them without complaint. Between the supermarket rye I used to buy and the fresh whole rye I use now, the gap has run to about five percent of the flour weight, which on a loaf carrying eight hundred grams of rye is forty grams and quite enough to spoil the crumb.

Stage 04Write it up

Keeping flour in a flat with no cellar

Whole rye contains the germ, the germ contains oil, and oil goes rancid. Sacked white rye will sit in a cupboard for a year without complaining, but whole rye ground last week has perhaps eight to ten weeks in a warm kitchen before it starts to smell faintly of old nuts, and a loaf built from it tastes slightly bitter in a way that is very hard to place until you know what it is. That was two wasted bakes before I worked out what I was tasting.

Five-kilo sacks now get split the same afternoon they arrive: two kilos into a sealed tub for the month ahead, the rest into bags in the freezer, where the oil stays where it is. Frozen flour needs a few hours on the counter before it goes anywhere near a bowl, because cold flour drops the dough temperature and the whole fermentation runs late behind it. The tub gets wiped out and properly dried between sacks, which sounds fussy right up until the first time you find a moth.