Can I make sourdough starter with raw potatoes?

In a sourdough starter, the bacteria and wild yeasts feed on starch. This is why bread is usually made from grains, which are very high in starch. Potatoes are one of the very few vegetables which have enough starch to work in a bread. So the idea for a bread from other vegetables won't work. Sweet potatoes could be OK, but definitely not carrots. You could look into the starch content of other tuber vegetables to determine if there are some good enough for your purpose.

As for the raw part, I highly doubt that it will work, again because of the starch. It is present in the raw potatoes, but it is enclosed in the cells, behind cell walls of celulose. When cooking, the cell walls soften and burst (this is why a cooked potato is soft and a raw one is firm) and the starch is released, so it is made available for the sourdough fermenter organisms. I am not 100% certain that it's impossible, but let's say 90%.

If you want to create a dough with a high proportion of vegetables, you could use normal sourdough starter as barm and when making the final dough, use pureed vegetables (raw or cooked) or a vegetable juice instead of water (after adjusting for thickness). If you think that you can get interesting fermented flavors from adding the vegetables to the starter, you can again use them as the liquid in the starter, not as the flour. But I am afraid that fermented vegetables will taste unpleasant, similar to vegetables gone bad after being forgotten somewhere. Still, it could be an interesting experiment.

Yes! I'm currently attending Le Cordon Bleu for Baking and Patisserie. I'm in the breads class right now, and my text book has a recipe for a potato sour with raw potato. Here..

8 oz Bread Flour 6.5 oz Warm Water .16 oz (1 tsp) Salt .16 oz (1 tsp) Sugar 1 Large Potato, peeled

1. Mix together the flour, water, salt, and sugar into a smooth soft dough. Add potato.

2. Place in sterilized bowl. Cover tightly with muslin or other clean fabric so the starter can breathe. Let rest in a warm place for up to 24 hours, until the mixture becomes frothy.

3. Stir well and cover with plastic film. Leave to stand 2-3 days in a warm place, until the mixture becomes light and foamy. Stir thoroughly each day.

4. Pour the fermented starter to a glass jar and store in the refrigerator for approximately 3 days, or until a clear liquid collects on top of the mixture. This indicates the mixture is ripened enough for use.Carefully pour all the liquid collected on the surface into a measuring jug, discarding the solid mixture that remains on the bottom. The weight of the liquid should be greater than the weight of the water used, because some of the flour will be poured off with the liquid.

My mother-in-law has been baking her own bread for almost 60 years using yeast made from raw potato. She usually takes a medium-sized potato, grates it coarsely and mix it with about 3 desert spoons sugar and 1 desert spoon salt and warm water in a glass jar. This is left in a warm place until the mixtute becomes foamy. A couple of raisins could be added to speed up the process. The liquid which would serve as the yeast, is then drained off and added to the flour. The remaining grated potato should not be discarded as this becomes the starter for the next batch of bread. It should be stored in a container in the fridge until needed.

Yes, you can do it it, but you'll need to cook and mash/puree the potato first. The cooking inactivates the potato's enzymes, breaks down the potato cells, and kills the spoilage microbes present in the raw potato. When combined with cooking, pureeing finishes breaking down the potato's cells and makes their starch and sugars accessible for your sourdough to digest. Oh, and retain part of the starchy water from cooking the potatoes; you will need this to make the mixture wet enough for the sourdough, and the extracted starch gives them more available food.

As with all changes in sourdough feed, make the change-over gradually; start feeding the starter with a batch of half-flour, half-potatoes, and then switch over to just potatoes after a few feeding cycles. This will make it easier for the yeasts and bacteria in the starter to adjust to the change.

To get proper results with other vegetables, you'll need a lot of starch content. If you cannot get a flour made from the vegetable, I wouldn't expect a sourdough to live on it. Sweet potatoes and parsnips should work. Chickpeas, beans, peas, and lentils may work if cooked well (retaining as much starchy water as possible) and pureed. With all these vegetables, cooking and pureeing is suggested.

The yeasts in sourdough can also ferment sugar-heavy vegetables, such as beets, carrots, onions, or tomatoes, but the results are similar to sauerkraut or kimchee. Don't expect the starter to thrive and propagate using these foods, but it may make for an interesting experiment nonetheless.

Foodgeeks has a sourdough starter recipe featuring grated raw potato. It still calls for white flour in addition to the shredded potato bits. I haven't tried it, and it's unreviewed on their site, so your guess is as good as mine about how the starter turns out.

So, to answer your question: No, it seems that nobody on here has tried it before. Try it and report back - you could be the first!

My grandmother put a whole raw potato in what appeared to be a typical sourdough starter otherwise. She kept it in her refrigerator and made biscuits with it regularly. The potato stayed in the starter. I wish I would have known I needed to ask her some questions about this before she passed...I don't know if she switched out the potato or how often if she did, or how she fed the starter, but I do know she made some dang good biscuits.

Im a little late on this debate. However, my husband tells me that his grandmother used to make her bread starter with potato peel and lemon juice. Once started, this culture used to sit in a warm place and be fed sugar and probably flour regularly. Bread was made each day for the family. How are you going 3 years on with your experiment. I'm interested in doing something like "grandma" used.
Gwen

If you cook the potatoe you will kill the bacteria you are trying to capture. Cutting the potatoe peel is enough insult to break cells to release starch: hence why peeled potatoes turn brown: oxidized starch. I am still a staunch believer that your starter community should match the material you're fermenting: if you're making wheat bread, you want to use a starter that has captured and concentrated the bacterial and yeast community that naturally feeds off it. I think potatoe is probably only necessary if you don't have whole grain flour: refined flour has been stripped of the grain layers where the bacteria lives.

My mother used a large chunk/chunks of raw peeled potato in a jar of thin (almost water) starter as a way to keep a yeast culture long-term without needing fed. Then a day or few hours before baking she would use some of this to jump-start her actual starter. Seems like she mixed flour and water with a spoonful of her pre-starter. Seemed to be a reliable low maintenance method for someone who doesn't bake regularly. But this was 30 years ago and I lack any details.

Bernard Clayton has a raw potato starter in his "Complete Book of Breads".

I'm basically ignorant in most of this, but logical in other ways.

If sugar is being added to the starter mix, I suspect that defeats the idea of how the "old People" did it... their access to refined sugar would have been limited. (Especially Country folk) I know of these such instances where nothing but potato water was used to feed the starter.

Two thoughts come to my mind: 1) if sugar is used, then sugar dependent Wild Yeasts that are present in the Culture are being activated. 2) If only Starch, (not sugar) is causing fermentation then we are on track. That then suggests that an enzyme (in a symbiotic relationship with a particular Yeast type) is present. This enzyme converts the starch to the sugar that feeds the yeast.

I'm thinking this line of thought backs up the idea that the "old Folk" were using uncooked potato in the CULTURE mix. Cooking in any shape would destroy the relevant enzymes.

Summary: Wild yeast plus "Natural" enzyme plus accessible (Cooked) potato starch = The Potato Sourdough Culture everyone is after.

Therefore we should, maybe stick with the formulae using Raw potato as the basis of finding the the appropriate Bio organisms that create the majic.

Hope that all makes sense.

In the Complete Book of Outdoor Cookery by Mel Marshall, 1983, pages 95 -96, the writer discusses a sourdough starter made from 3 medium potatoes, 2 cooked in 3-1/2 cups water, the third left raw (??) but peeled and 2 level tablespoons of the pulp added to 2 cups of the potato broth in a sterile jar, then add 3 tablespoons of all-purpose flour or durum wheat flour, to create a "sourdough" starter for bread. The book also describes how to maintain the "sponge" which can be kept for years.

It adds that "potatoes stored a fungus that made an excellent yeast substitute" and that this was known in the 1800's, and even for hundreds of years.