Dan,

I decided that refrigerator storage was making my cultures mild. So
I've moved them to the cellar. If you can find a place that's about 55
degrees F, perhaps a north window, and if you keep the starters firm,
they will begin to correct. Warm refreshment cycles will help.

I cannot do a better job explaining it than Gaenzle does. The
Wing/Gaenzle discussion helps a bit too. Both are found on Samartha's
site. Gaenzle's paper is not complicated but it is dense. Meaning there
are a number of levers to fool with. I urge you to read it. I had make
a graphic step-by-step outline to get it straight. So I am no rocket
scientist with this stuff.

The gist of it is... you have to manipulate both heat and hydration
levels during the refreshments. Pay attention to the business relating
to the effects of acetic and lactic acid. They do different things.

A warm final proof helps too. I saw your pictures. That's a good
direction. The heating pad is radiant. It's better for dough than hot
air.

My equipment is cheap and simple.

A $5 mini crockpot from WalMart with a plastic lid and and "keep warm"
setting.

A thermometer calibrated for low temperatures... 60-120 degrees. ie: a
yogurt thermometer.

A $5 securtiy timer to cycle the crock pot on and off. Otherwise "keep
warm" gets to 120 F.

Samartha uses aquariaum/terrarium heaters, see his site for details.
And while you're there read the Detmold material, look at Samartha's
calculator. It fits with just about everything Gaenzle discusses,
especially the inoculation ratios (which relate to acids which relate
to LB density).

Your hot pad might do the job, meaning you only need a thermometer.

Will