I am new to all grain brewing and have been doing extract for quite some time. Recently I have upgraded to an electronic HERMS brewery. I have a question about mashing that I thought someone may know.
First a little background information:
My brewery consists of 3 15 gallon kettles, one is my HLT with the heat exchanger inside the other is my boil kettle, and finally my mash tun is a 15gal blichmann kettle with the blichmann false bottom. I haven't installed temperature controllers yet so my HLT and boil kettle are controlled manually with a variable knob. I had planned to do my first run with this new setup this Saturday. I have 9.5lbs of grain to be mashed in for a 5 gallon batch.
After doing some research I have found that most people suggest between 1.5 to 2 quarts/lb for the strike water. I haven't yet compensated for the space the bottom of the blichmann kettle takes up. But based off those numbers I should use about 3.3 to 3.5 gallons of strike water. My issue is that my thermometer doesn't submerge until about 7 gallons of water. Thus I wont be able to get an accurate mash temperature reading (its unfortunate that it ships that way) so what I was wondering, is there any way I could make that thermometer read? I thought about using up to 7 gallons for mashing but then read that using that much water for the amount of grain could cause the mash to dilute and throw off my numbers.
I suppose if all else fails I could entirely depend on the HLT's thermometer to know what the mash tun is at, I did some wet runs with the system and found that the HLT sits about 10 degrees higher than the mash tun. So if I were mashing at 152 I would need the HLT to be 162 to compensate for heat loss as it recirculates. But I would rather have as much knowledge and control of the temperatures to give the best chance of having a successful first all grain brew.
I have a second question, Is there any harm in recirculating during the mashing process? or is it better to let the grain steep for one hour before recirculating for however long then sparging out? Also is there any harm in the possibility of adding oxygen to the mashing process since the recirculation port is sitting above the water level?