A 1-shot carbonate version takes a long time to make but the Quercetin capsules,stored in their container , last indefinitely.
Suitable for occasional use of staining developer.

QS-1
Metol .............................0.1g
Quercetin........................0.5g
Sodium Carbonate anh......2.5g
Water to........................500ml

Weigh out solids into container, add 500ml just boiled hot water, stir, filter through cotton wool (the Quercetin does not all dissolve)
Develop 30min 20C.