long term starter storage

1.  Freeze some, in sealed bag, remove as much air as possible. Mine lasts 4 months in freezer.  It's temp related, so a really cold freezer might mean shorter survival time.

or...

2.  Add flour to make it a stiff starter, maybe 60 % hydration, let it sit out at room temp a little, so the beasties can feed some and grow (you don't have to see expansion), seal, and then leave in fridge.  It will keep longer that way, but I'm not sure how long.

#1 and #2 are good options to share starter with a local friend, if they are not going to begin feeding and using it right away, or if you do not want to risk a spill of 100% hydration gooey-ness.

or... 

3. Dehydrate some. Spread your 100% hydration starter thinly on parchment paper or waxed paper.  I leave it in countertop oven, or main oven for 48 hours. Peel off and crumble.  Store sealed at room temp.   You can also use a dehydrator with fan, but use low or no heat.  I forget what the max temp is.  86 F or lower ought to be safe, and not kill off the beasties.   This way has been known to last years, up to decades. See  https://breadtopia.com/drying-sourdough-starter-for-long-term-storage/   for a video on this method.

#3 is good for traveling with, or mailing someone a "copy" of your starter.  Grind it to a fine powder, double bag it, and put in envelope. It is what www.carlsfriends.net and commercial companies do ( www.culturesforhealth.com and www.sourdo.com )

I do #3 as a regular "backup" of my starter.  But #1 is easiest, and #2 is next easiest.

-- When to backup/preserve:  

To get the most bang-for-your-buck, you want to maximize the number of yeast and bacteria cells, since most will die off in option 1 and in option 2.   And maximizing cells or "spores" for option 3 allows the fastest restart/revive with the smallest sample.  So I would start the preservation process at the same point in the feeding cycle as when you use a sample for baking:  at peak expansion after feeding.

-- To revive: 

1. To revive frozen:  I let it come up to room temp, and then feed as normal, 1:1:1, once a day.  But since most of it dies off, it does take a while, 2 or 3 or 4 days to come back to normal behavior after a feeding.  Be sure to discard as you go.

2. To revive refrigerated and stiff starter: Let come up to room temp, re-hydrate to normal %, then feed as normal. And again, it may take a while, and discard as you go.

3. To revive a dried or dehydrated starter, see http://carlsfriends.net/revive.html      Main thing is to start small, 1/2 tsp of the starter powder is fine.  Rehydrate and let stand for 15 minutes before feeding.  Go slow. Don't feed like you normally feed a living starter.  Mine takes 3 days until it "blooms" again.   Also see: https://breadtopia.com/faq/how-to-reactivate-dehydrated-starter/ for their written instructions, and here: https://breadtopia.com/starter_instructions/  for a video.

--

When you see the revived starter bubbling and behaving as normal after a feeding, it will "work" (in quotes).  But, it may take longer, up to two weeks or so, maybe more, before it really _performs_ as leaven, while the LAB and the wild yeast balance out again.

Just in case their web site goes away, here's a copy of http://carlsfriends.net/revive.html

(Their stuff is not copyrighted. They do it as a public service.)

The Brochure available for download here is a historical document. It is a lightly edited version of the brochure that Carl sent out with starter. The instructions in the brochure work just as well as they always have. However, with the fresh start that we are sending out, we have found that potato starch, from potato water or dry granules, and sugar are not necessary to reconstitute the starter. Plain white flour and water will do just fine.

Following is a method to revive the start that I like better than the one detailed in the brochure:

1. Get a small container. Begin with one tablespoon of lukewarm water, stir in 1/2 teaspoon of your starter and let stand for a few minutes to soften the start granules. Then mix in one tablespoon of flour. Depending on the flour, you may need to add an additional teaspoon or two of water. You want the mixture to be like a thin pancake batter.

2. When the mixture gets bubbly, put it in a little larger container. Then stir in 1/4 cup of water and 1/4 cup of flour. When that mix rises up add 1/2 cup of water and 1/2 cup of flour. When this bubbles up, you will have about one cup of very active starter that is ready for use or storage in your refrigerator.

The time between refreshments will depend mainly on temperature. You can expect the first sign of starter activity to take from four to 12 hours.

Tips:

o I use the baby formula wrist test to judge the temperature of the water. A few drops on your wrist should feel neither warm nor cold.

o A baby food jar and an 18-ounce peanut butter jar work well for the small and large containers.

o Established starter will do fine in any room temperature that is comfortable for humans. Warmer room temperature is helpful when reviving start, but do not go over 85F if at all possible. Cooler temperatures just extend the time required. If room temperature is under 68F, I find a warmer spot such as the top of my refrigerator or a cold oven with the light on.

o Vigorous stirring of the mixture from time to time will slightly shorten the time between growth stages, but is not necessary for success. I use this method to test start before shipping and just stir enough to mix the ingredients.

Regarding the vinegar "kick", and the use of dry yeast in a few of the recipes Carl transcribed, we don't do it, but heck, it might work for you.

Good luck with your sourdough,
---
"Carlos" October 19, 2003

Note: If your starter doesn’t bubble within 12 hours, just go to the second step and add more flour and water. Some tap water has too much chlorine so filtered water can be helpful. Keep adding flour and water every day until it bubbles. Old starters can take a week of this to revive so don’t give up until then.

Actually the best method I have found is to dehydrate the starter and then freeze.  I have kept start viable for up to three years in the freezer.  It will be less in an automatic defrost freezer

Tips:

Use a glass or hard plastic jar with a tight fitting lid

Grind or crush the dry start

for longest keep time use plain flour to fill in the space in the jar to exclude as much air as possible

If you want to use the refrigerator to store the starter, you can add enough flour to the liquid start to make a putty like consistency;  This will store for several months.  To restore, use a 1/2 teaspoon of the putty mix and follow the directions to revive dry start.

(Carlos)