Recently, other bakers have suggested that there is no need for acidification to help get a sourdough starter going. Instead, a process using whole grain flours, careful temperature control and an somewhat anerobic environment are purported to help get a starter going in a short period of time.
So what is the role of pineapple juice, or other acids, in combating the "stink" that sometimes develops in a sourdough culture?
I can only share my own (limited) experience: I had a starter that I had neglected for several months in my fridge. It had some sentimental value, as it was developed close to 5 years ago. A month or two ago, I took it out, saved 1-2 tbsp and started to feed it 1-2x per day at room temperature. Even after about 5 days, it still stank in not a pretty way. It was not an "acetone" or "nail polish" stink (which I've had, mostly related to alcoholic fermentation); it was not a pleasantly cheesy "parmesan" stink either (which I've seen in some young starters); it smelled a bit of sweaty feet, somewhere between vinegar, sulfur, and something slighty sharp, almost rotten.
My best guess was that as Debra has suggested, Leuconostoc or other stink-producing bacteria had taken a hold of my culture. So I did what Debra suggested: fed my starter with fruit juice. In my case, I fed it with the juice of a fresh squeezed lemon, and the King Arthur all-purpose wheat flour I usually feed it. I did this only twice. The starter smelled a bit "lemony" for for those 2 days, and then I returned to feeding flour and water as usual. However, after those two days, the nasty "stink" was indeed gone, and has stayed gone for weeks. (I am feeding it more regularly now, maybe weekly, but it still hangs out in the fridge most of the time).
In fact I think both Debra's and Ars Pistorica's methods will work effectively. To me, aspects of both methods are complimentary and do not contradict one another. So if you boil them both down, what are the key elements?
- Use whole grain flour to start a starter. (I think there is little disagreement that lactic acid bacteria live on most whole grain, and at least one study that backs this up.)
- Keep it warm but away from light: you want to keep your new starter between 86-98F (30-37C). Light will kill yeast.
- Be patient. It will take at least 4 days to get a starter going, under optimum conditions. In less than optimum conditions, it can take 10 days. In addition, many believe that it can take 10 days or more for the overall "flavor" of the starter to improve.