Baking sourdough bread necessarily involves obtaining and maintaining a starter culture. After experimenting with several ways of doing it, I settled on the lowest effort yet still effective one I found: the NMNF ("No Muss No Fuss") starter, courtesy of dabrownman on The Fresh Loaf.
The author's details in the recipe are worth studying, but to summarize:
- It's a stiff starter using whole rye flour. I normally use freshly milled rye but it also worked with store-bought whole rye flour.
- Building it involves 3 stages. Precise temperature control is not critical but is useful if aiming for a particularly sour taste (see details in the recipe link above).
- The first 2 stages are 4 hours apart. The starter should double in size 4 hours after the second feeding. If it does not (this happens when the starter was in the fridge for too long), remove the amount fed in stage 2 (water+flour) and restart from stage 2.
- Once the starter rises 25% in volume after the 3rd feeding, store it in the fridge in a covered container. I normally refresh it after about 2 months.
- To bake, I use about 10-15g of the starter (roughly a large scoop with a teaspoon) to make a preferment with whatever flour I'm using for that particular bread.
- An incremental preferment build as described in the original recipe is not necessary but can be useful if aiming to precisely control taste and/or to make the starter last a longer time when baking often.
The ingredient feeding amounts for each stage depend on how much starter you want at the end: