I brewed with my flat sculpture for the first time last weekend. Loved it. Had a great time.
I do have a question about holding temps during sparge/lauter though. This was my first time with a pump driven system, so I may be doing something wrong. Here are the broad steps I took. My main questions deal with items 5-6:
1. Heat sparge water and strike water on their own burners using the temp controllers on the control panel
2. Add grain to MLT, stir to break clumps and even out temperature. Start timer once I leveled at mash temp (did this in about 5 min from dough in)
3. Mash, allowing pump to recirculate my wort from the MLT to the heat exchanger as needed to control mash temps. This worked like a charm. I stayed within my differential despite the fact that the ambient temp was about 45F on Saturday.
4. Use MLT burner and pump to bring my grain bed to mashout temp (after about 15 min, I was having a hard time getting it much over 165F, so I just held it there for another 10. I figure the cold temps this weekend contributed to this)
5. Sparged using the float switches to maintain water level in my MLT. Sparge water was set at 175F
6. The grain bed stayed at 163-5F throughout the sparge until right at the end. I noticed that first, my sparge water dropped below the level of the thermometer and thermowell in the HLT and that burner kicked back in. I turned it off, figuring that my readings were now off since my probe was not longer submerged in water. I killed the flame because I didn't want to sparge that last bit with excessivly hot water.
That's when things got a little confusing. I was recirculating my sparge water through the HERMS coil to clean it while I sparged. I figure a combination of me killing the flame, the bulk of the HERMS coil being above water now (since most of the sparge water was gone) and the 45F ambient temp all contributed to my temperature drops.
I noticed that over the last 15 min or so of my sparge, the temperature of my grain bed dropped back to about 156F. I was not terribly worried as I had already likely denatured the mash emzymes with the initial mash out at 165F. And the bulk of my sparge was completed with the grain bed at that temperature.
I'm just wondering what I can do to keep my grain bed in the mid 160s throughout my sparge next time.
I only had 10 gallons of sparge water. I am thinking about going to 12 or 13 gallons for my next batch. Water is relatively cheap. The extra couple of gallons should help me keep the HERMS coil (and hopefully the temp probe) covered. That should keep my sparge water in the proper range and allow me to keep my grain bet warm enough. And anything I don't use for sparge can just be used to clean out pumps and pots at the end of the day.
Any other suggestions I might consider?