Originally Posted by runs4beer
If the strike water for batch 2 was heated in a cooler with an element installed in it which was powered by a 15amp (better yet 20amp) 120v wall outlet, I would think that you could reach strike temperature in less then a one hour boil. Sparge water could be preheated from water exiting the chiller (chilling batch 1) and then heated in the real HLT before the MLT drops in temp much, maybe? If the batch 2 strike water was collect earlier (day before) and could come up 20° to room temp that might help.
I like your thinking with using the chilling water output for sparge! That’s a pretty nifty time saver there even if it’s not up at the 170 degree mark straight out of the chiller.
I was thinking about volumes, and for ten gallon batches I am usually forced doing double sparges of approximately 4 to 5 gallons each. My thinking here is that I may be able to end up with enough hot water left over to use for the second batches strike and thereby start mashing as soon as the first batch final runnings are drained to the BK (and the mash tun emptied and refilled with new grain).
Here’s my (latest) rough process plan:
1. Start off with an absolute full HLT (~15 gallons) set at ~170 strike temp. I don’t consider this really a time-loss here since I usually have the water measured out the night before anyhow. All this would take is going down to the brewery as soon as I wake up (who doesn’t do this everyday anyhow?) and flipping a switch. Go back upstairs and get my coffee started like I normally would. A timer could make this even easier.
2. Strike volume is typically around 7 gallons. Get the mash going and fill the HLT back up to full. For 60 degree tap water temp the new average temp of the full HLT would be ~120F. Should be back up to 170 very quickly (prior to first runnings).
3. First batch sparge ~5 gallons. Fill HLT back up to full (new average temp of full HLT = ~135). 15 minute rest of the first sparge while the HLT is on full blast should get the temps up but honestly I don’t think it needs to get to 170 since the second sparge is really just rinsing the grains further (conversion should stop during the first sparge).
4. Second batch sparge ~5 gallons. Allow the rest of the HLT volume (~10 gallons) to continue rising to new strike temperature (carefully entering new higher MLT start temperature in Beersmith). Once strike temp is hit, switch power to BK element.
(OPTIONAL STEP – AUGMENT HEATING WITH SEPARATE HEATING ELEMENT, PROPANE BURNER, ETC.)
5. Drain second sparge into BK.
6. Clear mash tun and add second batch’s grains. Add strike water (approx 8 gallons).
7. When first batch is done boiling, shut off BK element, chill with plate chiller where output water is sent to HLT. I think this water can sometime be up in the 150’s depending on flowrate. As soon as the HLT element is covered switch power back over to HLT.
8. Clean BK and finish rest of batch 2.