Originally Posted by ahoym8e
How critical is the sparge temp? I don't have an insulated hot liquor tank at the moment, so i will start my liquor off at 170, but I might lose 10 degrees or so before it's all run out... BAD or just bad?
To sparge, you want to keep the temperature of the grist and sparge water at 165 - 170 degrees. Lower temperatures will reduce efficiency, and increase the probability of a stuck sparge; while higher temperatures will cause excess tannin extraction. According to Dave Miller, you can decrease the tannin extraction by acidifying the sparge water to a pH of 5.6 or less. With your grain bill, you are unlikely to get a stuck sparge, but if you add a pound of flaked barley, you might.
If you start sparging straight ofter the mash, then your mash temperature will probably be in the low 150's, and you will need some pretty hot water to raise this to 165 - 170.
I "mash out" by adding a 1.5g of 200 F acidified water, which raises the mash to about 170. I add the water before the grain, which helps to prevent the grain bed from getting compacted (which with my system is very likely to cause a stuck sparge). After 15 minutes, I recirculate a couple of gallons before starting the sparge. The recirculation cools things down a bit.
For the sparge, I heat acidified water to 190, and add it to a 5g cooler that had been pre-warmed with hot water from the tap (about 140). By the time it has meandered though the plastic tubing and out of the sparge arm, the temperature has dropped considerably, but the grist being sparged stays below 170.
Since I started the mash out and increasing the temperature of the sparge water, my efficiency has increased by about 10%.
I have an older version of the sparge arm that you described. It works great, but has a couple of idiosyncrasies.
First, there is a big temperature drop between the HLT and the exit from the sparge arm. You need to increase the temperature of the water in the HLT to allow for this.
Second, you need (at least, I need) a considerable head of water to force any water through the sparge arm. With my set up, I need at least 2g of water in the HLT to get anything out of the sparge arm. Your mileage may differ.
I'd do some experiments to determine the temperature drop between the original temperature of the sparge water, and the outlet from the arm; and to determine how much head of water you need to get any output from the sparge arm.