Hi I'm a first time all grain brewer and noticed this fine floury trub at the bottom of my wort after sparge. Is that protein or starches? Grain bill: 0.8 kg Gladfield light pilsner malt 0.8 kg Gladfield wheat malt 0.25 kg Gladfield Toffee 0.25 kg Gladfield Rye 0.25 kg Rolled Oats (and yes, my wort is thick a syrup, no it didn't get stuck) Mashed at 60-65C (150F) Iodine test is inconclusive. Turns a very dark brown only after thorough stirring. Crash cooled the wort to 1C (32F) as I ran out of time for the boil. Suggestions?