Mash temperature control Grainfather S40

[jambop]

Hi I use a Grainfather S40 brewing system and by and large find it is good enough for my purposes. There is one area that I think the system could be improved quite a bit it is temperature control of the mashing process . The temperature control on the S40 is pretty shonky if for example you choose to mash at 67C the controller actually allows the temperature to drop to 64.9C before boosting the temp again to 67C . Now I have no idea how these systems are calibrated but that would indicate to me that the actual mashing temperature is well below 67C for the greater period of the mash. Of course this may for lots of brews be fine but what if you want a more specific temperature for your mash? Does anybody have an opinion on this subject as to the effect on the wort you hope to make over the wort you actually make due to this variance in temperature and if so what it is likely to be and how to overcome the problem if there is one.

 

[OLBrews]

Just unboxed my S40 and ran a quick temperature test using 5 gallons of water (approximately full volume for a 3 gallon batch). Target mash temperature ran 2-3 degrees F higher than the temperature set on the S40 based on two digital thermometers. Brought the unit up to boil, and sure enough I had full boil at 209 F (I am near sea level, should be 212 F).

Also confirmed the 2-3 degree F swing on the unit when cycling the heating unit during the mash (again using just water). Setting the element to 1000W during mashing lessened the temperature swings, the higher element setting led to hot spots 5-6 degrees F higher (even when recirculating). I am not overly concerned about this level of deviation but would prefer if this was tighter to the intended temperature.

Have contacted Grainfather about the temperature offset and plan on further testing with water volumes for a 5 and 10 gallon batch in case the location of the temperature sensor isn't ideal for the smaller batch size.

 

[hawkwing]

I doubt this temperature difference matters a whole lot. It doesn't need to be within 0.1 degree.

I found the bigger issue was the mess the recirculation makes. Can't have the lid on and the included recirculation arm doesn't go to the center of the lid. So if I were to cut a hole it wouldn't be in the center which I'd prefer so I could put a tri-clamp fitting in the center.