Using sourdough technique with instant yeast
Does using sourdough techniques with instant yeast lead to overproofing?
For several reasons I cannot make my own sourdough starter. So I make all my bread with SAF Instant Red label. However, I would like to make artisan style bread with open crumb. I've experimented with the variables but some general characteristics of my technique:
- Bread flour (often 20% whole wheat)
- high hydration (70% - 80% or higher -- including a small percentage of olive oil)
- Poolish (50% of the total flour and water with a scant amount of yeast and rested for 12 hours)
- Autolyse (mix rest of the flour and most of the water and rest for 1 hour)
- Mix yeast with rest of water and mix into dough. Rest 20-30 min.
- Mix in salt +olive oil.
- Stretch and folds. I've done only stretch and folds, e.g. 3-4 spaced 30 - 45 min apart, or kneading + 2 - 3 S&Fs. (The intention is for S&Fs to lead to an airier crumb and more holes)
- Bulk rise in room temp -- until dough seems doubled and (preferably) light and jiggly.
- Shape -- rest -- sometimes in fridge overnight or more briefly at room temp.
My results have been mixed. My crumb tends to have a nice springy texture and good flavor. But I rarely get consistent big holes. And my dough often deflates when coming out of the banneton before baking and doesn't really spring a lot in the oven - whether cold retarded or not. (Note that I have a funky old oven in a country (Japan) where gas ovens are almost non-existent. So my oven temp might not be high enough)
My question: This process means the total time from mixing to end of Bulk Ferment is about 4 - 6 hours. (Sometimes after the S&Fs, the bulk rise gets exceedingly slow). Am I fooling myself that sourdough technique can be used successfully with instant yeast; am I just risking and perhaps experiencing overproofing? Might the instant yeast burn itself out during the hour or two of kneading and stretching and folding? After all, instant yeast is designed for bakeries and faster rising times. And given the longer bulk process, should I be using more or less instant yeast? I've experimented between 1% an 2%. But I'm always confused whether a longer bulk requires more or less yeast.
Thanks for your thoughts!