John: Hey this is what a forum is for, thank goodness for the other folks on here or I would be lost a most of the time.
Okay, I used 25 lb of malted 2 row barley
then ground it down using a Valley Mill
In the mean time I put 15 gallons of filtered water into a Hot Liqour Tank ,a converted keg, and brought the water up to strike temp ,170dF,. Once we hit strike temp we mixed the water and grain in a mash ton ,another converted keg,. Once all the grain is doughed in the temp usually drops to 148dF to 150dF. Ours hit 148dF on the nose. I kind of do this by eye, but if I had to say I would say I put about 10 to 11 gallons in with the ground up grain.
That we let sit for 90 minutes making sure it maintained the temp. I just puled out 25L ,6.5gallons, for the scotch. I sat that aside to cool and went on to make beer with what was left in the mash ton and the sparge tank ,Hot liqour tank,
After the 25l cooled I took a hydrometer reading and come up with 1.050. I was really looking for 1.070. That was when I decided to add the DME. Two pounds later I hit 1.068. As I was out of DME that became my OG. That was Saturday, it is now Monday night and it is bubbling like crazy. Next Saturday I plan to move it to a secondary to clearify, then wait three days before I distill it.
I think your turkey frying keg will work great as a mash ton but I wouldn't use it for a fermentor. I think you will have much more flexibility if you use a foodgrade plastic bucket or conical for fermentation. Another advantage of not using it for fermenting would be that you can be mashing your next batch while your first is fermenting elsewhere.
Wow it looks like you have resourses to spare. I've never tried using raw sap, but I can't imagine why you would need to cook it down. The best thing to do is try a batch and see if it turns out then of course report the results here for the rest of us.
By the way, I also have a batch of rum fermenting. I used 15 lbs of dark brown sugar and one bottle of molassas in 25l of filtered water. My OG was 1.110! That one knocked the airlock out of the top of the fermentor. For a normal sugar wash I usually go with an OG of 1.10.
I hope this helps.
Cheers!