Make your own sourdough culture
A sourdough starter or natural leaven is essentially a combination of wild yeasts with wild bacteria, in a medium of flour and water. Whilst it can take several months for a culture to develop to a point where it is very active, you can get a culture going from scratch in a week or less, if you’re lucky. The luck part depends on what yeasts and bacteria get cultivated.
The yeasts can come from the grain, from the air or from you! The bacteria that establishes will be a lactobacilli, as in yoghurt. Wherever a culture is created, and maybe by whomever, it will be unique. This is why different cultures from around the world create different bread characteristics, or work better with some breads than others (in our bakery, we use five cultures for the different breads we make).
Here’s a recipe which you can try, and if it looks good, you can use it to make a real home-grown sourdough.
Mix 60g organic whole wheat flour, 60g organic rye flour, and 120ml filtered or mineral water. Cover loosely with cling film and leave at room temperature (60-65F or 16-19C) for 48 hours.
Mix and throw away half of your 240g. Add 60g mixed wheat/rye flour, and 60ml water (‘refreshing the culture’). Cover loosely and leave at room temperature (60-65F or 16-19C) for 24 hours.
Day 4 and continuing: Repeat as day 3.
By day 5 or 6, the culture will be speeding up, and you can begin to refresh more frequently. When fully active, 12 hours will bring it to maximum activity levels, ready for baking.
Note – some starters are made using, grapes, raisins, yoghurt etc. It’s worth trying this sometime, but quite unnecessary.
Whatever you do, do not use yeast or sugar, as some daft books tell you.
To keep your culture alive and well for evermore, keep in the fridge in a sealed container. You only need to keep a few tablespoons at a time. Each week, get it out, throw away two thirds, bulk up to the original quantity with equal amounts of flour and water, leave out for 4-6 hours, then put back in the fridge.
To make sure you don’t lose it sometime, pass on to you friends. If you’re as barmy as I am, take it on holiday with you too to keep it alive. Never freeze it.