Central to the process of Sourdough making is the process of fermentation, which arises from the development of naturally occurring yeast in the dough. The process differs slightly from sourdough to that of commercial bread making where a commercially developed baker’s yeast is added to the dough. This is where the starter comes in to play.
The starter is a symbiotic microbial ecosystem of wild yeast and lactic bacteria that have set up camp in a mixture of flour and water. The nature of the starter depends on the relationship that exist between the lactic bacteria and ‘wild yeast.’ Therefore, each starter is different. A large contributor to this, is that a microbes choice of food greatly affects the type of bacteria that it will mingle with. As such starters made from flours created from grains grown in differing soils and environments will create a different taste to the next. The flour with which you refresh the starter, the temperature at which you refresh it and and the environment in which it is stored will all contribute to the flavour profile it produces.
The starter is a unique living ecosystem of microbes and although there are many combinations of bacteria and yeast present there is usually one dominant type of yeast and several species of lactic acid producing bacteria (lactobacilli) present. Lactobacilli are responsible for increased dough acidity. This is why sourdough is more nutritious and digestible. Lactobacilli are key to the development of the dough, as it breaks down the starches in the flour into simple sugars which are then consumed by microbes which in turn produce lactic and acetic acids, giving sourdough its characteristic flavour profile.
Once the yeast has access to oxygen aerobic fermentation takes place. Once the fermentation ball is rolling and access to oxygen falls the fermentation process changes to anaerobic fermentation (similar to fermenting beer). At this point the yeast produces both alcohol and carbon dioxide (CO2) by using up the simple sugars created by the enzyme breakdown form lactobacilli. This release of CO2 is the cause for the bubbles which you find in the bread and is what makes bread rise.
Equipment; Jug, mixing bowls, kilner jar or glass jar, wooden spoon or spatula, clean tea towel.
Liquid Starter;
140 g rye flour
100 g strong bread flour
240 g water at room temperature
10 g clear honey
Liquid Starter;
- Day 1 – Mix together 20 g of rye flour with 20 g of water in a bowl and mix in 5 g of honey. Cover with a clean tea towel and leave in a warm place for 24 hours.
- Day 2 – Bubbles wil have begun to form on the surface. In a larger bowl mix together 40 g of rye flour and 40 g of water and 5 g of honey. Mix well and stir in the mix from day 1. Cover with a clean tea towel and leave in a warm place for a further 24 hours. -NB- This is the process of refreshing the starter.
- Day 3 – The mixture should now be bubbling quite happily and should certainly now be noticeable. Mix 80 g rye flour and 80 g water in a large bowl and mix in the starter from day 2. Leave to ferment in a warm place for a further 24 hours covered with a clean tea towel.
- Day 4 – To the mix made on day 3, add the strong flour, 100 g water and stir well. Your starter should now be ready to use. The consistency of the starter at this point should resemble a pancake batter. Store it in a glass jar. The starter can be stored airtight in the fridge but should be fed or refreshed every 3 days. -NB- Take note of the weight of the glass jar on its own. This will become apparent as you read on.
Feeding/ Refreshing’
The starter will remain alive for around 3 days. At this point if you wish to keep the starter, it is wise to refresh it. Thus this should be done at 3 daily intervals. This is done by adding 50% of its weight in flour and water.
For example this morning when I refreshed my starter the total weight of the jar with the starter in was 1033 g. I know that the jar in which my starter lives is 735 g so I simply minus that from the total weight to find the weight of my starter;
1033 g (total) – 735 g (jar) = 298 g (starter).
I then divide the starter weight by 2;
298 g / 2 = 149.
I feed the starter equal parts flour and water (149 g so; 74.5 g flour and 74.5 g water) -NB- I will have rounded up to 75 g which is of course fine.
The starter if left exposed to the air at ambient temperature will become active and will double in size after it is refreshed. This is when the starter culture is most active and is the best time to use it.
Leaven;
25 g active sourdough starter
100 g strong bread flour
90 g lukewarm water
Leaven;
In my previous post about baking Sourdough I referred to ‘leavened starter’ on a couple of occasions. The leaven is the base of your dough. It is a robust colony of microbes that have been recently refreshed. To make this mix 25 g of your active starter with 100 g strong bread flour and 90 g lukewarm water. Leave over night and the leaven will be sufficiently active to use first thing in the morning.
FORKIN DELICIOUS 