Starter refrigeration

You can keep going at room temperature for as long as you wish, and this is what goes on in most bakeries. The principal benefit of refrigeration is for the home baker who does not use the starter every day to bake.

As long as you follow a process that includes a proper feeding schedule (time), and feeding ratio (determines flavor, schedule and ripeness), and proper hygiene (avoid contamination of the culture), you will be fine. Contamination is most likely in the early stages of creating a starter. Once the culture is established it actually creates some active resistance to outside organisms, but this is not an absolute protection, so clean your utensils and containers. 

If you do not wish to feed every day, bring your starter into the refrigerator. They key to that is to feed the starter and let it "go" for an hour or two before putting it in the fridge. My starter is normally on a 12 hour feeding schedule, but once in the fridge it can stay there for long times. I did not use mine since my pannetone adventure in late December (vacation and busy work), and took it out just a few days ago. Let it warm up and complete its growth cycle (for me that means approx another 12 hours) and then do 2-3 regular feedings before use or putting it back in cold storage. My starter has not lost much of its zeal for growth in those 2.5 months.

--dolf


See my My Bread Adventures in pictures

Reading some people here, you'd think the goal was to get the starter into the fridge. "My starter has been going well for two days, so I'll refrigerate it now!"

Despite being a total sourdough fanatic, the only reason I put up with starters is because I want to make bread. Good bread. Sourdough bread.

It takes a while for a starter to mature. How long? It depends on who you talk to. Some people say a week. Others a month. Some say three months. Some say nine. That's when it is at room temperature and being fed regularly. I don't see that there is any reason to hurry the starter into the fridge, any more than than you'd want to put your kids into cryogenic storage.

I wouldn't even think about refrigerating a starter until it had passed the basic test. Has it made good bread for me? If it hasn't, I have no way of knowing if it's worth the space in the fridge that could be better dedicated to good beer than bad starter.

Now some comments on starter handling. I've been playing with sourdough for about 8 years now. I was a professional baker in a bakery that specialized in sourdough for one of those years, and I have been active in professional mailing lists and organizations.

The consensous is that starters at room temperature should be fed no less than twice a day. You can play with thicker starters, more massive feedings, and all sorts of other things, but starters at room temperature that are fed less than once a day have a habit of going astray, of declining, of becoming less active over time. Each feeding should be at least enough to double the size of the starter. So, to 1/2 cup of starter I'd add about 1/4 cup of water and 3/8 cup of flour. To 50 grams of starter, I'd add 25 grams of water and 25 grams of flour.

Once refrigerated, the starter can go some time between feedings. How long? It depends on lots of things. Like the starter. The refrigerator temperature. The thickness of the starter. How long before it was refrigerated the starter was last fed.

The strong bias at my web page, sourdoughhome.com, is to make sure the baker has a healthy starter when they start to make sourdough bread. I get lots of unhappy emails from people who don't follow my advice. One time the sourdough takes 2 hours to rise. The next, it's 16 hours and no rise. This leads to sourdough dropouts. So, I give really conservative advice. I want people to succeed, rather than leading them down the path towards how much starter abuse they can get away with and still make bread. All of which is to say, there are safetly margins in my suggestions. However, you explore them at your own risk.

In general, refrigeration does not preserve a starter, it just slows its death. The yeast and bacteria are still doing their thing. Slowly. Sooner or later, they will run out of food. Sooner or later, the acidity will get too high and that will kill the critters. It will just take longer in a refrigerator than at room temperature.

Before I refrigerate a starter, I make sure it can make good bread. Then I feed it until it can rise to at least double its size after it's fed. If it can't double its size, it isn't really healthy. If a starter keeps failing to thrive, I find feeding it three times a day, and enough to triple its size, will usually revitalize the starter. If the starter seems bland, let about 5% of the flour be whole wheat for a few feedings. (About 1 TBSP per cup of flour.)

Once the starter is rising to double its size between feedings, feed it one more time and immediately put it into the refrigerator. This assures you that the acidity of the starter is low and the starter has lots of food, both of which help the starter survive better.

How long can the starter stay in the fridge? I like to take the starter out once a week or so and feed it until it's happy and healthy. That said, I have left the starter in for considerably longer periods and it has always revived after a day or three.

Signs of starter distress:

1. Hooch forming on the top of the starter. Hooch is a clear liquid that has alcohol in it. This is a sure sign that the starter hasn't been fed in too long.

2. A liquid layer forming in the center of the starter. This is a sure sign the starter has been fed too much water and too little flour. 1 cup of water and 1 cup of flour (an often quoted ratio) is too little flour. Use equal parts - by weight - of flour and water.

3. Starter discoloration. If the starter turns gray, it's been too long since its been fed. Other colors can indicate more severe problems,and I'd discard a red, pink, blue, green or whatever starter and start over.

4. Mold. Sourdough starter actively resists mold. If mold grows on starter, that is a clear indication that things have really deteriorated in your starter. The best bet is to discard the starter, sterilize or discard the jar it was in and start over. If this was your great-grandmother's starter and you just have to save it, it can be done. Email me for instructions.

I am again conservative when it comes to using the refrigerated starter. I want the starter to be lively and healthy before I use it. I'll take a tablespoon or so of the refrigerated starter, mix it with 1/4 cup of water and 3/8 cup of flour. This high dilution reduces the acidity. 12 hours later, another 1/4 cup of water and 3/8 cup of flour. 12 hours alter, 1/2 cup of water and 3/4 cup of flour. 12 hours later, the starter should be very active. If you have enough starter, use it. If you don't have enough, feed it again. In a few feedings you will have commercial quantities of starter.

What about feeding the storage starter? I feed the starter the way I just described. When the starter is happy and healthy, I discard the starter in the fridge, clean out the bottle, feed the starter one more time and then put it into the freshly cleaned bottle and back into the fridge.

What about vacations? I just leave it in the fridge for vacations of two months or less.

Hope that helps,

Mike

Thanks for answering my questions before I asked them. Dave