Hi Nick,
If there's channelling whilst trying to use the HERMS to raise temp, then it won't be recirculating through the grain properly, and the temperature won't be uniform.
I don't have any recirculating temp control, so don't have any experience here, but i'd assume that removing the channelling would be a positive thing.
What size batches are you doing, actually what size mashes are you doing? i'm looking at getting a RIMS or a HERMS, but have been leaning towards a RIMS as they have better response times, but i haven't heard anyone getting 3degrees per minute with either RIMS or HERSM. I may reconsider if the ramp times are comparible.
Cheers,
Alan
If you restrict the flow, the wort at the outlet of the heat exchanger will increase fast. BUT the grain bed and the wort in it will lag behind dramatically and you wont have uniform temperatures. To me, you want the fastest flow without sucking down your grain bed to get the most uniform temperatures resulting in the most repeatable brews.
I wasn't thinking of that when I asked GB about ramp rates
here. He said he got 1c per minute using a 1800-2000W element in a 100L batch.
But for a 100L batch (as per linked thread) allowing 70L strike water and 15kg grain (light grain bill) with a 2400w element, mathematically using 100% cycle, I would only be able to achieve from 66 mash to 78 mash-out 30 minutes minimum, allowing zero losses. 12/30 = 0.4c minute. Try the numbers in any water heating calc (inc the one on my website).
If will apply the same rules to a single batch,
water at 20L in the mash and 5kg grain, so I use the water value 25
temp diff 12 (66 mash to 78 mash-out)
2400w element,
and using the same calcs we get 12degrees/9minutes, so 1.3c per minute possible at 100% cycle.
If you get faster ramp rates, then your mash is lagging behind. As a minimum I would calculate the heating potential of the element on your mash volume, and recirc for at least that amount of time, if not a bit longer.
QldKev
edit: Add pic of sparge arm
Normally this is run under the surface of the wort, this was just at the start of recirc'ing to have a look at it. I added more water after the pic was taken.
QldKev