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Going on vacation: How to keep starter alive?

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May_be's picture
May_be

Going on vacation: How to keep starter alive?

To those of you who've successfully been maintaining starters for years now:

I'm a newbie bread baker. I've grown two starters from scratch, both using Reinhart's methods. The first one is a white starter made using the pineapple juice method. The second one is a wholewheat starter made using the mash method. I've been keeping them both in the basement at about 70-72F. The first one I'm feeding daily, at 80% hydration. The second one is very new, I'm just on day 7 and have mixed it into the mother starter at 75% hydration. So far they both seem to be behaving well, the first one is rising after each feed and winding down by the next one, and the second one seems to be working just as Reinhart describes in his method. The starters are pretty new, and I've only baked a couple of loaves with th first one which were clearly not perfect - somewhat dense crumb and over-sour flavor - but that may be for a host of other reasons as I discovered while browsing this forum. 

Which brings me to my question, which is, what is the best way to keep them alive when I'm on vacation? I will be going away soon for 18 days. Do I stick them in the fridge and just feed them when I come back, or should I get my neighbor to come in to feed them from time to time when I'm gone? If the answer is the latter, how often should I request the feedings?

Thanks in advance.

Maya

breadforfun's picture
breadforfun

Hi Maya,

I recently returned from a trip about the same length as yours and I kept my 100% hydration starter in the refrigerator during my time away.  I refreshed it the night before I left and left it out until it started to form bubbles, then refrigerated it.  The important thing is to be sure the beasties have food while you are gone, so don't let the starter get fully ripe and start to collapse.  Mine came back after a couple of 1:2:2 refreshes when I returned.

I have also successfully frozen a bit of my starter, then revived it a few months later.  You could try both methods as extra insurance.

-Brad

 

May_be's picture
May_be

Brad, thanks for your prompt reply. I normally feed right after breakfast, and I have an early morning flight, so if I fed it just before I left the house I think the beasties would have the most food, right? Or is it necessary for it to become bubbly before refrigerating it, in which case I would feed it late the previous night and refrigerate it early in the morning.

Also, when freezing the starter, I'm guessing you can just thaw it out in the fridge overnight before returning to the feeding schedule?

-Maya

breadforfun's picture
breadforfun

Hi Maya,

I normally feed right after breakfast, and I have an early morning flight, so if I fed it just before I left the house I think the beasties would have the most food, right?

If you are confident that you have good activity, feeding it early and refrigerating immediately should be fine. 

I'm guessing you can just thaw it out in the fridge overnight before returning to the feeding schedule?

Yes, or even room temperature.  They take a little time to wake up.

Have a good vacation!

-Brad

GAPOMA's picture
GAPOMA

Maya,

There are times that I like to (or sometimes must) put my starter away for a while, then take it back out when I'm craving a good sourdough again.

I have had a starter going for a number of years now.  To put it away I first make sure I've got a healthy starter at 100% hydration.  I then make it into a 65% starter by taking 50g of starter and adding 40g of flour and 10g of water and mixing well.  This makes a nice stiff starter.  I then put it in any small plastic container with a lid, label it, and store it in the back of my refrigerator.  (Recognize, you can use any multiple of starter/flour/water in the same ratios and get a 65% starter.  FWIW, I usually keep either a 50/40/10 = 100g or a 100/80/20 = 200g starter in my refrigerator as an "emergency backup" just in case disaster strikes.)

I just brought my starter back out yesterday morning (July 25th).  It was 200g and had been in the refrigerator since May 20th (about 9 1/2 weeks).  I took it out, added 200g water & mixed, then added 200g flour and mixed.  By late yesterday afternoon it had doubled and was bubbly all over.  Today it looks great!

At least this works well for me, and it's worked more than once.

- Greg

Doc.Dough's picture
Doc.Dough

Feed 1:20:20

Wait 1 hour.

Refrigerate at a temperature between 1-3°C.  This will last a month if it has to (better a week than a month, but it won't die in a month)

When you get back, take it out and let it come back to room temperature.

Feed 1:10:10 and let it sit at room temperature for 12 hrs.  If it looks normal, refresh again at 1:10:10 and you are good to go. If it is slow, let it go another 12 hrs before you refresh again.

May_be's picture
May_be

Greg, thanks. I'll leave it in the fridge without worrying too much about it while away!

Xenophon's picture
Xenophon

Hi Maya,

Agree with Greg and recently also had to make sure my starter bridged a 6 week gap while I was away.  Most important things are (based on my experience):

- Make sure you have a vigorous, healthy starter going, I don't think it would be a good idea to try this with a very recently established one.

- Feed, and keep at ambient temperature until bubbles start forming, then wait another half hour.

- Refrigerate and keep at low temperature.  I actually divided mine:  half stayed in a tupperware container in the fridge at 4 centigrade (39 Fahrenheit), the other half was frozen at -23 centigrade (-10 Fahrenheit).  Both did well upon my return although the one that was kept frozen did take almost 24 hours after thawing to bounce back.  I presume this is because a proportionally higher number of yeast cells died off in the freezer but there's no way of really knowing.  Would be interesting to see a study about the effects of freezing over time on relative proportions of the yeast/lactobacillus populations in the starter.

 

Anyway, both freezing and refrigerating worked for me.  I did feed it daily for a week after returning, just to make sure everything went back to the original equilibrium before I started using it.

 

I also read an article (but can't remember where) describing someone taking 'smears' from a starter on parchment paper, letting the starter dry, then putting it (in dried form) in a pot and the freezer.  Apparently this would also work but I didn't try it.

 

 

 

hanseata's picture
hanseata

is easy. You just have to smear your freshly fed starter over parchment paper or a clean cutting board, so that it's a thin layer. Let that dry for a few days, and then scrape the flakes off into a ZipLock bag, empty jam glass or other container with lid. Place sourdough flakes in the fridge, they keep forever.

To revive them, simply mix them with lukewarm water, and give it enough time to wake up.

This dry starter you can even pulverize and use instead of baking powder.

I keep some rarely used specialty starters in dry form, like a chickpea starter for Arkatena bread.

Usually, when I go on vacation, I follow Richard Bertinet's advice to feed the starter, and refrigerate it. And if it has a dark surface and even water puddle on top, when you come back, you can scrape the top layer off with a spoon and feed the rest.

Karin

 

 

May_be's picture
May_be

Thank you all for your input. I'm so happy I discovered this forum, it's wonderful to be able to learn from the collective experience here. Most bread books do say you can store starters in the fridge, but of course that assumes that you bake at least weekly. In Tartine Bread Robertson writes about one of his recipe testers who took her starter with her on vacation! I don't plan to do that :)

Doc.Dough - your method to use a very small inoculation ensures there's a lot of food for the beasties even in the fridge, correct?

Xenophon - I think I'll do the same as you and store half in the fridge, half in the freezer. 

I'll report back on how my starters did when I'm back from vacation!

Doc.Dough's picture
Doc.Dough

Yeast and LAB have growth rates that vary with temperature.  The LAB always grows faster than the yeast (shorter doubling times).  As the temperature goes down the yeast slows down more than the LAB does so that the LAB becomes the dominant factor in determining when you need to feed and how much you need to dilute the starter when you refresh.  It goes like this:

LAB grows and produces acid

Acid reduces the pH of the starter and increases the acidity (total titratable acid or TTA).

TTA and pH are not interchangeable, can vary independently, and drive different phenomena.

LAB growth rate (reproduction rate) slows to a halt as the pH goes down to about 3.8 but it still continues to make acid which contributes to increasing the TTA without changing the pH very much (pH can get down to 3.6 or a little lower)

Meanwhile the yeast grows pretty much without regard to either the pH or the TTA but at a slower rate than the LAB.

The yeast stops reproducing when it runs out of food - which is well after the LAB has stopped growing.

Then they both start to die off.

You should refresh after the LAB has stopped reproducing (pH is stable and below 3.8) and before the yeast runs out of food - preferably sooner.

When you refresh, you need to be aware of the TTA and what it does to the post-refresh pH.  High TTA requires a higher dilution factor to push the pH up into the zone where the LAB can grow fast enough to do their job.

The relative growth rates of LAB and yeast as a function of temperature can be found in Ganzle's paper (along with their joint sensitivities to pH, lactate, acetate, and ionic strength).

The myth about "washing" a starter that has been too long in the refrigerator is just that.  What you are doing is to dilute it enough to get the post-refresh pH above 5 so that the LAB can grow well.  This is accomplished by refreshing at 1:10:10 or higher.  A healthy starter will need refreshing after about 12 to 16 hrs at warm room temperature if it is fed at 1:10:10.

Feeding at 1:20:20 is only enough food to allow for one more doubling time in the refrigerator (over what happens with a 1:10:10 refresh) and if the original starter is mature (good acidity/tastes sour to the tongue) when you do the refresh there is no real risk that you will push it over the edge.  You don't want to feed it so much that the pH gets up into the range where leuconostoc can thrive (because it will), even though everything happens at a snail's pace when cold.

Hope that helps.

 

 

 

 

 

Doc.Dough's picture
Doc.Dough

Freezing does not work (lots of easy experiments if you want to prove it to yourself).

Drying does work, but it is not a sure thing.

You can put a teaspoon of starter in the middle of five pounds of flour and stick it in the refrigerator.  This is good for a VERY long time.  When you get home, dig out something that is gooey and refresh it.

May_be's picture
May_be

Hopefully my starters will be the better for it!