Sorry, this is gonna be a bit long, but Iím looking for some expert advice/critique.
I normally do partial mashes. Last week I did my first all-grain brew, an ordinary bitter BIAB, but my iodine tests seemed to show that I never
achieved full starch conversion (saccharification). I read (somewhere) that getting particulates in the test sample could cause a false negative, and although I was careful to get clean samples I hoped that was the issue and went ahead with the brew. After the boil, the wort in the fermenter was some of the clearest Iíve ever made, so Iím confident that I didnít boil a bunch of starch and make beer-gravy, but I still have questions.
Recipe and process:
OG: 1.037 FG(est): 1.009 IBU: 29.8
5lbs Maris Otter
8oz crystal 40
9oz sucrose (late addition)
1.5oz fuggle aa4.0 60 min
1.5oz fuggle aa4.0 10 min
Optional - 0.5oz EKG dryhop 5 days.
Mash 60 mins at 154F
The MO was crushed at my LHBS, I crushed the crystal and victory myself in my burr coffee mill at the widest gap setting - Iíve done it before for small amounts, never had a problem. Paint straining bag went in my 5 gallon cooler, grain went in the bag with a handfull of rice hulls. I stirred the dry grain up well.
I poured in 7 quarts of 171F water into the cooler and stirred up the mash. The temperature was a little below my target, so I ladled in some 200F water, about 8-10 oz total, until the temperature got to 154F. Put the lid on the cooler and let it sit. After 20 minutes I stirred the mash and did an iodine test, which came up negative. Let the mash sit another 20 mins, stirred and check conversion, still negative. I stirred some more, hoping I could ďhelpĒ it, and let it sit again for 10 mins, by this time the temperature had dropped to 150F. Stir, check, still negative. Left it for the last 10 minutes. The wort was very sweet, as I would normally expect.
Mashed out with 3.75 quarts of 200F water, let it sit for 10 minutes. Pulled the grain bag out of the cooler and squeezed the hell out of it to get all the good stuff. Then the wort went into my kettle. Since I simply donít have the capacity to do full boils at this time, I did this as an all-grain partial-boil, which I know is unconventional, but itís what I can do right now. The boil and cooling proceeded normally, and I hit the estimated gravity, 1.037, exactly.
Now a week later, the beer looks good, tastes good, and Iíve got a gravity of 1.010 - thatís close enough to the estimate Iím okay with it. Iíll let it sit in primary another two weeks, it may or may not lose that last gravity point, but Iím not concerned about it.
Are there any obvious problems with my procedure? I get my temperatures and numbers from BeerSmith. All of the water I brew with is carbon-filtered (Pur tap filter). Iíve never tested or adjusted the pH, or added any minerals or other water treatments. Should I?
Or should I just assume the iodine tests were wrong somehow? Is there a trick to doing them correctly? I took a spoonful of liquid from the wort and a drop of iodine in the spoon. Usually this shows me conversion by a half hour or so into the mash.
Any input is greatly appreciated!