Greta

Patchiness at this stage usually means the rice was too wet or clumped. Steamed rice for koji should be firm enough that grains separate when you rub a handful between your palms. If it smears, the spores only colonise the surface of the lumps.

Mix at night and bulk while you sleep if your kitchen drops in the small hours. My best summer loaves come from a 10pm mix with very little starter.

Agreed. I go 3.5 percent for anything I will keep on the shelf for a year and accept that it looks boring for the first week.

Try one loaf with 50g starter instead of 100 and everything else identical. Halving the inoculation doubles your margin for error on timing, and the flavour is better too.

The two things that reliably give me kahm are too warm and too much air above the brine. 21C is on the high side for kraut, I get much cleaner ferments around 18C, and it also stops the cabbage going soft. Not urgent, just the reason it keeps appearing.

The things that would actually worry me are fuzzy growth, pink or orange streaks, or a smell of rot. Sharp, boozy, vinegary and solventy are all just points on the normal spectrum of a hungry culture.

Four hours cooling is plenty, so it is not that. If you want to prove it is bake and not ferment, cut a loaf in half and look at whether the gummy layer has the same open structure as the rest, just wet, or whether it is dense and closed. Wet but open means bake. Dense and closed means the dough compressed, which is a shaping or handling issue.

Overworked, not dying. Two things happened at once: your grain mass has grown while your milk volume stayed the same, and the kitchen went up several degrees. Both push the ferment faster, and rapid over-fermentation is what splits it early. Either drop to a teaspoon of grains per 500ml, or keep the grains and go to a litre and a half of milk. The sliminess usually comes with heat and a very active culture, and it clears once the ferment slows down.

Light coloured plastic rather than the black ones everyone sells. Is the difference big enough to matter?

Retard, and it is not close for a working week. The fridge is what turns bread from an event into a background task: you do 15 minutes of active work in the evening, the dough sits cold for 12 to 20 hours, and you bake straight from the fridge with no warm up when you get home the next day. You also get better flavour and a much easier dough to score. The shelf space problem is real but a shaped boule in a banneton inside a bag is about the footprint of a large mixing bowl, and you can retard in the same tub you bulked in if space is truly tight.

Makes sense. Any preference between the flat glass discs and the ones with a little handle?