First starter attempt failed; no idea why.
A couple of weeks ago I made a first attempt at making a starter. Unfortunately after about a week it developed a very strong acetone smell which, after much googling, I found out meant the starter was underfed. Opinions seem to be divided on whether or not a starter can be rescued from such a state but I decided to throw it out and start fresh. Before I make another attempt, though, I'd really appreciate any insight into what exactly went wrong, so it doesn't happen again.
Some basic info:
- I started with a combination of whole rye flour and plain flour, gradually reducing the amount of rye starting from day 3.
- I was feeding the starter every 12 hours at a 1:1:1 ratio for the first 5-6 days, then I switched to 1:2:2.
- Temperature in my apartment hovers around 20C, which I think should be fine.
- I first noticed the acetone smell around day 8, I think. Until that point the starter hadn't been doubling between feedings, but it started to do so around the same time it developed the smell.
What I don't understand is this: how is it possible that I was underfeeding my starter when it showed no signs of doubling for so many days? If the yeast were so hungry for more food I'd expect the starter to double over the 12 hours (isn't that a sign that the yeast have eaten all their food?) - but until the smell developed it never did. As far as I can tell I had no way of knowing it was being underfed before it was too late. I was also feeding at 1:2:2 at that point, giving the yeast twice the amount of food even before they started doubling the starter (at the risk of diluting the colony, I guess) - and still it was too little? And at 20C I wouldn't expect the starter to be so active - from everything I've read that seems to be a rather low temperature for developing a starter, so wouldn't it take the yeast more time to go through so much food, rather than less?
I'm sure I am missing something here... anyone know what could've went wrong?