If you are just developing a starter from scratch, it should be reliably active from feed to feed. This means it should increase in volume and become shot through with evenly distributed bubbles of gas (that cause the increase in volume). The amount of increase is not super critical as it depends a bit on the type of container that you use (tall narrow ones will rise higher than wide shallow ones). Also it should not smell of any 'nasty' substances, maybe a bit yeasty or a bit like sour milk or vinegar. Definitely not nail-polish, vomit or rotten eggs. It is best to follow through the the recommended seven to ten days of development rather than rushing in too soon so that the culture has come into balance and stabilised and should be almost bullet-proof as far as nasty bacteria, fungus and mould go.
If you are preparing a levain for a loaf of bread then it is often recommended that you mix your dough about when the levain peaks in volume and before it starts to collapse. However, it is possible mix starter culture straight into the dough though you do run the risk of the culture being not active for some reason and not getting a leavened dough and a poor loaf as a result. Fresh culture or collapsed levain might just take a little longer as they have to (re)activate with the new food source in the dough. Some people recommend dropping a small dollop of the levain into a container of water and seeing if it floats. However, I feel that this is not necessary as, if the levain has risen and is full of bubbles, then it will certainly float and merely confirm what observation should tell you.
I fully agree with what was said before. Regular bubbles are the best indication.
The volume is a good measurement, too but it depends a lot on what type of flour you used and how much water you added. Rye starter with a 1:1 water-flour ratio should increase 2.5 times by its original volume. Wheat starter (again 1:1) is much more liquid and will barely double. Wheat starter with a 3:2 (3 parts flour, 2 parts water) ratio should tripple its volume. In any event it is best to use a tall narrow container, because it keeps the warmth better than a shallow one.
Please don't try to make a wheat starter with a 1:1 ratio float. It won't. All it will do is dissolve itself and you'd have to add flour and wait another 20 hours. Only thick starter such as rye with 1:1 ratio or wheat with 3:2 ratio float. By the way, letting the starter float is a good preperation before you put it to rest in the fridge. Yet, it messes with your dough hydration if you let it float instantly before you bake.
If you're not sure whether your starter is ready just add some yeast to the dough (1% of the used amount of flour). Keep feeding your starter. After three weeks constant feeding it should be ready to be used without commercial yeast.
Hope this helps and good luck!
Alice
Replies
Hello pauldo,
It depends what stage you are at.
If you are just developing a starter from scratch, it should be reliably active from feed to feed. This means it should increase in volume and become shot through with evenly distributed bubbles of gas (that cause the increase in volume). The amount of increase is not super critical as it depends a bit on the type of container that you use (tall narrow ones will rise higher than wide shallow ones). Also it should not smell of any 'nasty' substances, maybe a bit yeasty or a bit like sour milk or vinegar. Definitely not nail-polish, vomit or rotten eggs. It is best to follow through the the recommended seven to ten days of development rather than rushing in too soon so that the culture has come into balance and stabilised and should be almost bullet-proof as far as nasty bacteria, fungus and mould go.
If you are preparing a levain for a loaf of bread then it is often recommended that you mix your dough about when the levain peaks in volume and before it starts to collapse. However, it is possible mix starter culture straight into the dough though you do run the risk of the culture being not active for some reason and not getting a leavened dough and a poor loaf as a result. Fresh culture or collapsed levain might just take a little longer as they have to (re)activate with the new food source in the dough. Some people recommend dropping a small dollop of the levain into a container of water and seeing if it floats. However, I feel that this is not necessary as, if the levain has risen and is full of bubbles, then it will certainly float and merely confirm what observation should tell you.
Hope this helps and good luck with your projects.
Farinam