SoopirV900
Member
I thought I was lucky when I walked by one of the labs at work and found a pile of equipment that was free to take, for in the middle of it all was a Fisher Thermix stir plate (model 120MR)! I googled the heck out of this thing; I was concerned about the name given it- THERmix lead me to think it was a combo-hot/stir plate. Nothing turned up, and it only has one adjustment, so I opened it up to make sure there was no heating element in there- there wasn't. It sat in my closet for 2 years before I worked up the courage to tinker with yeast (am starting to culture and slant now too). On my last batch (brewed Saturday, two days ago) I planned ahead and activated a Wyeast pouch of American Wheat (Wed). I decanted some of the yeast into a sterilized (pressure cooker for Father's Day!) tube for slant innoculation, and the rest went into a DME starter of ~1.040 (Thurs). I dropped in a stir bar and proudly christened my plate. The next morning (Fri) I checked on it, and the starter was quite warm (almost HOT
). The inside of my flask was dripping with condensation, and while the flask itself was not uncomfortable to hold, it was way warmer than my fermentation would be. The airlock was bubbling nicely, but went to a negative pressure state not long after I panicked and set the flask on the counter. Checking before I left for work showed a mild switch to positive-pressure, but no bubbling (I thought I killed my yeast). To jump ahead, I pitched anyway after brewing (Sat), and the next morning (Sun) I had supreme blow-off, so the fear of killing my friends was unwarranted (this time!).
Before I scrap this plate, is this detrimental to forming a solid starter? All the biology i ever learned is telling me that warmth is good for growth of microbes (yeasties included), but I can't shake the feeling that I'm growing weak critters- too many advantages at a young age lead to disappointment later, right? I didn't have any way of accurately and cleanly measuring the temp of the starter on the plate, but with a 78'F house and quite warm to the touch, I'm guessing it's between 90-100'F.
FWIW upon reinspection of the mechanism for this model, it's an old-school (open tap) rheostat controlling an open-winding AC motor. The armature is what appears to be heating up. Is there an electrical fix for this (can I install a more modern and efficient pot to control speed)? Props to all you guys with Cigar box stir plates, but I'm kinda trad- I love the idea that I'm using lab-grade equipment. Perhaps Fisher Sci capitalized on an over-heating stir plate and called it a TherMix to claim that both the heat and the stir were intentional?
So, to recap a horribly long post (sorry!)- Making a starter is good (accepted), but is a starter grown at a higher temp than primary bad? IOW, would I be better off forgoing the mixing in favor of a lower starter temp? This one worked, but now that I'm slanting and such, I'm opening myself up to greater degrees of failure.
). The inside of my flask was dripping with condensation, and while the flask itself was not uncomfortable to hold, it was way warmer than my fermentation would be. The airlock was bubbling nicely, but went to a negative pressure state not long after I panicked and set the flask on the counter. Checking before I left for work showed a mild switch to positive-pressure, but no bubbling (I thought I killed my yeast). To jump ahead, I pitched anyway after brewing (Sat), and the next morning (Sun) I had supreme blow-off, so the fear of killing my friends was unwarranted (this time!). Before I scrap this plate, is this detrimental to forming a solid starter? All the biology i ever learned is telling me that warmth is good for growth of microbes (yeasties included), but I can't shake the feeling that I'm growing weak critters- too many advantages at a young age lead to disappointment later, right? I didn't have any way of accurately and cleanly measuring the temp of the starter on the plate, but with a 78'F house and quite warm to the touch, I'm guessing it's between 90-100'F.
FWIW upon reinspection of the mechanism for this model, it's an old-school (open tap) rheostat controlling an open-winding AC motor. The armature is what appears to be heating up. Is there an electrical fix for this (can I install a more modern and efficient pot to control speed)? Props to all you guys with Cigar box stir plates, but I'm kinda trad- I love the idea that I'm using lab-grade equipment. Perhaps Fisher Sci capitalized on an over-heating stir plate and called it a TherMix to claim that both the heat and the stir were intentional?
So, to recap a horribly long post (sorry!)- Making a starter is good (accepted), but is a starter grown at a higher temp than primary bad? IOW, would I be better off forgoing the mixing in favor of a lower starter temp? This one worked, but now that I'm slanting and such, I'm opening myself up to greater degrees of failure.
