Tuesday, April 12, 2005

Rescue Remedies for Sick Yeast Beasties 

Say you have a sourdough starter, and it doesn't look or smell quite right. Maybe she isn't as vigorous as she once was. You're tempted to throw her out and start all over, even if The Lady has been around since the 1800's.

There are some rescue remedies you can try before you give up.

First, let's review some of the problems a sourdough starter can have.

The hooch - the brownish liquid the forms a top layer on the sourdough when she's been resting a while - isn't floating on top, but is hovering in the middle or even the bottom of the jar. This usually means the flour or the water introduced some element that's making your sourdough sulk. Remember when I complained about Tri-Plint not liking the water I used in his feeding? That's pretty much what the sourdough is doing - sulking. A little extra care and special water or fresh flour can make all the difference.

All sourdough cultures have their own fragrance, and it helps to remember what yours smells like when she's happy. The smell can range from a mild beery fragrance to an intense malty smell. It can be slightly sweet, especially if your flour choice is whole wheat or semolina. Rye flour sourdoughs tend to smell yeasty and earthy under the beer smell. Think dark German beer, and you get a hint of what that will smell like.

If the fragrance is off from normal, a little extra tender care can fix it. If the smell is badly off, the sourdough is also usually discolored - a pinkish tinge to the hooch is the most common discoloration.

And then we have the colored sourdoughs. Normally, a sourdough is a beige color with a clear brownish hooch floating on top. The beige can vary from really pale almost white to tans and even light browns if you're using whole wheat or rye flours as feeding flour. The beige part or the hooch can be discolored. The hooch can hold a pinkish tinge, go grey, or even have a green edging. The thick beige culture herself can turn colors - a parchmenty yellow, pinkish, green, or blue.

I've never been able to cure a blue sourdough.

If you're in the process of capturing a wild Yeast Beastie, and encounter any of these problems before you ever get to learn the characteristics of the culture, you won't have a backup of healthy dried culture vacuum sealed in your refrigerator with which to restart her, so this is what you can do:

1. Pour out all but one cup of your culture and throw the excess away. Don't even feed this part to the dogs. They won't like you if you do.
2. Wash and sterilize the jar.
3. Pour the cup of culture into the sterilized jar and top with bottled water (the cheap drinking water that 45¢ a gallon is fine). Stir it up really well and let it sit in a warm, draft-free place for 3 hours (that incubator you made to activate your culture is perfect).
4. Pour out all but 1 cup of culture, resterilize the jar, and return the cup of culture to it.
5. This time, feed her with 1 cup fresh flour and then fill the jar to within 2 inches of the top with bottled water.
Put her back in the incubator for 6-10 hours.
Pour out all but 1 cup of culture, resterilize the jar, return the culture to the jar with 1 cup of flour and 3/4 - 1 cup bottled water.

Put her back in the incubator for 3-4 hours.
6. If she smells decent, bubbles up within 4 hours, and a layer of hooch forms on top, you're good to go. You can either set her in the refrigerator until you're ready to use her, or use her right away.

This is usually enough to cure most minor sulks and ills. But if she's really sick or contaminated, it can many more such treatments to effect a cure. Sourdoughs are remarkably resilient and hardy. A weekend of extra care and they're usually back in baking form.

Sometimes, though, the contamination is more than finickiness. Stray bacteria in the environment or the allowable contaminants in flour overwhelm your culture, and the weekend regime isn't enough to restore your precious culture back to health and vigor. In that case, proceed on to Step 7:

7. If she's still setting the hooch layer in the wrong place or still smells off or is discolored, repeat steps 1-5. For badly sick or finicky cultures, you may need to try different brands of flour or water and repeat steps 1-5 until she comes out right, and that can take up to a week of washing and incubating every 8-10 hours.

Why yes, it does seem a bit excessive to hover over a culture for a week, setting your schedule by her feedings. Some cultures are worth it, though, for the sentimental value of the culture, for her unique flavor and characteristics, or because she's so old you would feel terribly guilty at killing her after all these centuries.

This is why I highly recommend drying a portion of your starter and vacuum sealing it against future need. Sometimes a culture gets so contaminated she can't be cured, and all you can do is wind the clock back to the earlier piece and branch off anew.

If you can store your dried cultures at a friend's house or even in a bank safe deposit box (cool, dark, dry), then you needn't worry about disasters depriving you of your cherished starter, either. Temperatures over 100º will kill your starter. An electrical failure while you're on vacation can end a promising culture in no time (and leave a smelly horrid mess to clean up).

A little TLC and a decent dried backup can make your relationship with your Yeast Beastie a healthy, happy, long-lasting one.

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