Hi I’m fairly new to all grain, 9 batches in. I brewed my first oatmeal stout yesterday and it was horrible; draining the mash I mean. The grist was 13.5 lbs of assorted barley and 2 pounds of the flaked oats NB sells. Oats was 13.1 or 13.3% on Beer Smith which I know is slightly high but still doable. Mash at 150F, 5 gallons of water. My mash was stuck! I tried blowing into the ball valve, added hot water, emptied into buckets, disassembled my ball valve and removed manifold. (manifold is cheap reinforced nylon tube with holes on the bottom wrapped in a circle; worked like a champ till now) I brewed before work and this stuck mash was beginning to present a real problem. In one last attempt I moved as much as I could to my old bottling bucket; let it settle and tried that-fail. In the onset of panic I removed/washed and began straining and lightly pushing the grain on top of my garage window screen. This worked remarkably well and I was honestly surprised at the little amount of debris in the wort. The time and mess it made a long with dumping it all back in the mash tun to (sparge) made this very unacceptable. The wort taste very good and I basically hit my pre boil number of 1.060 I got 1.059. Post boil still waiting as I had to leave and left it in my fridge. Took it out this morning. I love the style and want to continue to play with this recipe. Next time should I do a step mash? I noticed some gunk around the manifold holes. I thought flaked oats were pre gelatinized or whatever? Final note I also added .25-.5 LBs of rice hulls at mash in. How can I improve this lautering?
I just kegged an oatmeal stout that sounds pretty similar to your recipe with roughly 15% flaked oats from NB and mine lautered fine so it is doable. That said we do use a stainless steal false bottom for our mashtun. Could the nylon tubing have gotten crushed a little by the weight of the grain or was their actual grain clogging it? I’ve heard of this before, was this batch any bigger than previous ones.
When i do an oatmeal stout I use flaked oats and malted oats in about a 1:1 ratio. The malted oats have a major husk which I find helps a lot in lautering.
I have done a few batches over 13 lbs. It looked like the holes in the manifold were lined with gunk and then little pieces of grain collected to the edges. Maybe the plastic became sticky and allowed the oatmeal to stick easier collecting other grains. I just tried a cold sample and it has a wonderfully silky mouth feel so all in all I’m happy. I have been wanting a false bottom but keep reading bad reviews for the 10g GAT cooler kinds. In the next year I want to build a counter top system with two 10g coolers and the 15g bhlichmann pot, pump ect.
I will keep malted oats in mind also.