It's alive... but only barely. How can I give my sourdough seed a boost?
Last weekend I created a sourdough seed culture, more or less following the recipe in Peter Reinhart's wonderful Wholegrain Breads book. The only difference I made was that instead of pineapple juice, I used slightly diluted apple juice (apparently the PH of apple juice is around 3, so I diluted it a tad to try and get it closer to pineapple) since I didn't have pineapple on hand.
After a few days (and one feed) I noticed some very small bubbles on the surface, and after stirring these bubbles came back again overnight. I fed the seed again nearly two days ago and am currently on phase 3 as far as I can tell. I haven't started to throw away any of the sponge yet, because it hasn't become very bubbly and I am assuming that because of the temperature of my apartment (16C/60F) the culture is a bit slow. However, I realised today that when feeding the other day, the water I used was filtered and straight from the fridge, so that probably didn't help.
Right now I just transferred my seed culture to a glass dish so that I can see any bubble formation more clearly, and whilst formation is quite rapid now, the bubbles are not sticking around so it's difficult to tell if it's ready.
Is the reason for my culture's sluggish behaviour most likely due to the low air temperature or is another explanation more likely? Any tips for how to increase the activity of the culture? Should I feed it a little more (it's very wet and runny right now), warm it up (I have a radiator that I often use for proofing bread that is suitable), wait or do something else entirely? Any suggestions would be much appreciated.
Yes, you should warm it up. It will make all the difference in the world. You could also thicken it a bit if you want, but it is not necessary at this stage. Once it gets growing good you will definitely want to thicken it up or else you will be feeding it constantly.
Thanks, SourdoLady. I'll give that a try and see what happens.
Oops. I think I might have heated it too much. I left it for a while without checking the temperature. When I checked, it was nearly 40C/105F! It seems kind of dormant now, so I am worried that I might have killed it. There are a few small bubbles on the surface, but it is showing less activity than before. Perhaps the yeast (or other bacteria...) in the centre of the sponge is still living?
By the way, it smells a lot like vinegar. I don't have PH paper so I haven't been able to test the PH, but vinegar has a very low PH, so perhaps the solution is too acidic for yeast to thrive?
I doubt it is dead from 105°, but you are right about being acidic. Stir it up good and then take only a couple of spoonfuls of the old starter and give it a feeding. Start small--don't drown it with food until it recovers and shows life again. I'm guessing it will revive quickly.
If you haven't discarded any original sponge I would definitely recommend throwing away most of what you have at refreshing the rest with rye flour at a 1:1:1 ratio. That's about 2 tablespoons of your starter along with 2 tablespoons water and 1/4 cup rye flour. If you have a scale it's easy to just mix 30 grams of starter, water and flour. Whole rye flour works best to boost starters. You can also use whole wheat flour if that's what you have.
Keeping the starter in the high 60°s will also help it out.
After I thought I had killed it I decided to leave it for a couple more days to see if there was more activity. Whilst there was very little obvious activity at first, there were a few definite bubbles after 2 or 3 days so I decided to go to the next step and feed it anyway.
When I got home last night it had become a really airy sponge so I went on to halving it and giving it lots more flour and water. By morning (again, the air temperature was very low) it had risen significantly and by the time I got home tonight it was trying to bust through the plastic film I put over the top.
I just put my first mother starter in the fridge. It doesn't have a name yet, but it will soon. I will try and bake my first sourdough this weekend.
Thanks for the help, guys!