Wrox: Nice setup! I am slowly moving towards a setup like yours. I have the 20G Stout mash tun with bottom outlet and there are a few minor quibbles I have with it. First, the thermometer is nowhere near accurate. It is about 10 degrees lower than the actual wort temperature. I have no idea what causes this but think it might be due in part to stratification in the tun. Second, I would like to have had them tack on some SS mesh screen to the back side of the false bottom as I get a bit too much grain making its way out of the tun. I do direct fire recirculating mashes, BTW. If I was doing this with a RIMS setup, I would be afraid of too much grain getting into the tube and adding off flavors, but maybe I am overthinking that. Third, I tried to use the sparge arm during recirculation, but because of the false bottom issue, it clogs badly and means I have to change over from an elbow and tube to the sparge arm. Kind of a pain, but is workable. BTW when the sparge arm clogs, the pressure from the pumps causes a spray that makes a mess and screws up the grain bed. Don't try this at home kids, as it makes a mess!
Cleaning the tank is a bit of a chore as well. I can't imagine going larger than this and being able to clean in a home setting. I generally scoop out the mash and give it to a friend for his chickens, then I spray it out with a garden hose outside to get it mostly clean. I set it aside and then after pitching I give it a good cleanup with bar keepers friend, dry thoroughly, and put away until the next brew day.
Are you seeing the same thing with the thermometer and false bottom with your setup?
Cheers!
Hi Stonebrewer. Hopefully I can shed a little insight on these issues for you.
1. Mash Tun temp gauge. I originally had the same issues as you, and this is what I've found. First, the gauges are not calibrated from the factory, so the first thing I did was to fill it with 150 degree water. I used 2 different lab thermometers to check the water temp near the thermowell and then adjusted the dial thermometer to the same temp. I was still having some issues with the readings even after this was done. It would read consistently at one temp, and then be off at another. I even tried a second dial as I have 2 others from the HLT and BK and still ran into this problem. After some experimentation, I realized that the thermometer needs to be completely immersed to get an accurate reading. If you stick it into the thermowell dry, only the tip will be touching the thermowell at the end, and it will work very poorly. What I ended up doing is packing the thermowell with heatsink compound so that there is no air space between the dial thermometer shaft and the thermowell walls all around. This has stabilized the temperature reading over a wider range and it is also quicker to react to small temperature changes. This being said, I find it still takes too long to react to large temperature changes such as going from mash temp to sparge. It can take several minutes (10!) for it to get to where it is actually at and stable. I am currently still checking things with my lab thermometer to make sure I'm not overshooting during sparging, but I have confidence now that it's telling me what's going on during the mash. In the end I have to admit that I'm not a big fan of these dial thermometers, and am debating switching to an RTD and electronic temp reader. The RTDs I'm using in the HLT and BK are spot on and react very fast to temp changes.
2. False bottom. I don't have the bottom outlet tank as mine was one of the earlier ones with a side outlet. The false bottom does have a gap around the edge, but I can't see how you could get a perfect fit and still be able to remove it for cleaning. Mine varies from touching the walls to as much as an 1/8 inch to maybe even 3/16ths in areas around the circumference. I am recirculating through a chugger pump through a herms coil, and although I do see an occasional piece of malt flow through my hoses, it is very minimal and have never had any issues with clogging even when I felt I may have been recirculating a little fast. Is it possible you are going too fast and the increased pressure is sucking to hard?? I'm a little conservative with my recirculation as I'm afraid of the grain bed compacting and getting a stuck sparge or too much channeling and low efficiency. I also found that there is a sweet spot for heat transfer in the HLT herms. Too fast and the wort doesn't pick up enough heat and hold temp in the MT, or to slow, and I get the same thing because the recirculation is to slow to hold the temp constant. When I'm recirculating, I now watch the temp out of the elbow and tube and adjust for just about 2 degrees below the hlt temp. This seems to be working quite well for me . I'm averaging about 80 to 85 % efficiency fly sparging over about an hour to 90 minutes and get a very clear wort. My expected final gravity readings are also pretty much spot on.
I have never used the sparge arm for recirculation because of the following issues which I believe to be correct. Letting the recurculated wort sprinkle down creates two issues I'd be concerned with.
1. As it sprinkles down, you are going to lose a lot of heat as it is going to cool as it travels through air. This would make you have to heat the HLT quite a few degrees higher in order to get the temp you want which will change the enzymatic action in the wort. You would have to take this into account or you would be mashing at a higher temp then you think you are.
2. As the wort sprinkles, you are subjecting a large surface area of hot wort to oxygen over time which could lead to off flavors (cardboard)and a shorter shelf life.
This is why I haven't used the sparge arm for recirculation. The fact that your arm is getting clogged over time because of grain getting through the false bottom I now realize is another issue. I'm not sure it was meant to be used in this fashion. It does suck having to change over during the mash. I have dropped a gasket and clamp a few times doing it and I don't like having to work over hot liquid. In an earlier post, I had mentioned that if I would do any thing different I wanted to have 2 inlets on the top of the Mash tun for another reason, but this just added another. With 2 inlets, one could have the sparge arm connected, and the other the elbow and tube for recirculation. No having to change over. Brilliant!
Yes, cleaning the mash tun is probably the worst part of the brew day, but it is what it is. I'm not sure I would constantly use Bar Keepers Friend" every time though. Doesn't it take a lot of rinsing ?? I just use a little PBW and a blue scrubby.
Hope this long winded reply helps.