hafmpty
Well-Known Member
Long post ahead, partly so I can get it out of my brain, partly because I want to tell somebody and my wife doesn't care, and partly to get some ideas. 
I brewed yesterday (Ordinary Bitter from Brewing Classic Styles) and figured out an issue that has been plaguing me...and in the process created another problem.
I have 3/4" Tri-Clamp fittings welded to my MLT & Chugger pump inlet. And my diptube is 3/4" as well. I use 3/4" ID silicone tubing for recirculation. With this setup, a loose(ish) crush (.050), and some rice hulls thrown in on the false bottom I can recirculate during the mash very quickly.
BUT...I have (until yesterday) throttled the ball valve down quite a bit. It circulates, but not enough to create a giant cone of grain (which I can do with the ball valve open all the way).
Well, I was taking readings yesterday and noticed that there was A LOT of variation in temperature throughout the mash and the temperature reading on the PID. Something was wrong and has been from the beginning.
Luckily I remembered the sage advice of a member of my brewclub (catt22). He recommended keeping your fittings big (check), your tubing big (check), and your recirculation as fast as possible (NOT check).
I've been throttling my recirculation because it was the only way I could avoid getting a vacuum in the mash. But even still I would pull a pretty good vacuum anywhere from 20-40 minutes into the mash. I know this because, again catt22 had the brilliant idea of installing a vacuum gauge on your MLT outlet. So I'd pull a vacuum and have to stir and unsettle the grain bed. Not ideal especially for step mashes and longer mashes.
Well, yesterday, my temperatures were off, I was starting to get a vacuum, and I was getting pissed. The PID said one temperature, my thermapen said another, and a 12" probe thermometer (from Thermoworks...the makers of the Thermapen) taking a reading from the bottom of the mash said another). A classic case of stratification. And it seems to be common (or at least expected some what) in RIMS & HERMS systems. Well, I don't want it. I want my mash to be 152F when I tell it to be 152F and I want the whole thing to be 152F, not just the outside or the inside or wherever. BUT...I'm not going to invest in a mash mixer which seems to be the only given solution for avoiding stratification.
Well, I finally figured out the problem AND more importantly, the solution. By laying the hose in the mash (even with the float attached to keep it from sinking into the grain), I was inadvertently causing the suction. And the slower recirculation was causing the stratification.
My hose placement was (gradually) creating an easy path for the wort to flow down around the sides where the wort was circulating. But it was not going through the middle. I had created a path of least resistance. This led to the stratification as the hotter wort from the bottom wasn't being evenly distributed because the grain bed in the middle wasn't getting the warmer wort.
Not only that, but I was losing the large surface area of the false bottom that allows lots of wort to flow through down to the diptube. I was draining through the grain, but really only through the sides causing the diptube to suck wort out, which was compacting the grain bed around the center meaning even less wort was going through that part of the mash...hence the vacuum. And the cycle continued.
What added to my frustration is that I know from tests that I can recirculate 10 gallons through my MLT without creating suction in 1min 45sec. That means that every 1min 45sec every ounce of wort in that mash should be able to pass the RTD giving me an accurate temperature reading and have a chance to be heated up appropriately without any risk of scorching (direct fire).
THE SOLUTION...After getting frustrated, I calmed myself down and channeled catt22.
I turned off the pump, stirred the mash up really well, gave it a couple minutes to settle, and (remembering what catt22 said) I opened that ball valve up for a very quick recirculation...BUT I DID NOT lay the hose in the mash. I held the hose...for 90 MINUTES (60min for mash 15min for heating up to mashout and 15min for mashout). The whole time I was moving the hose of returning wort over the top of the mash to ensure even distribution of the hot wort.
After that, I didn't get ANY suction AND within 5 minutes every single one of my thermometers were reading the exact same temperature. The top of the mash was the same temp as the middle, bottom, outside, inside, RTD, etc. ABSOLUTELY NO TEMPERATURE STRATIFICATION and all because I increased the flow and stood there holding that hose.
So...lots of info (for those that care). But here's my problem and I'm trying to figure out a solution. I (obviously) don't want to hold the hose during the mash. I added automation so I could keep my temps consistent and be able to walk away. So I'm trying to figure out a solution that will distribute wort evenly over the whole grain bed. But because it's the mash, the mechanism I use needs to allow grain particles through and needs to be big enough to allow the wort to drain out but NOT squirt or jet out so much that it creates the same problem as before.
Any ideas?
I use keggles so the MoreBeer sparge arm is out (and it's expensive)...and I think my flow rate would have it squirting as it shoots into the diverter plate. I've thought about making something out of CPVC or perhaps using a stainless collander that hangs inside the keggle, but I'm not sure. Let me know your thoughts and if my experience helps you.
I brewed yesterday (Ordinary Bitter from Brewing Classic Styles) and figured out an issue that has been plaguing me...and in the process created another problem.
I have 3/4" Tri-Clamp fittings welded to my MLT & Chugger pump inlet. And my diptube is 3/4" as well. I use 3/4" ID silicone tubing for recirculation. With this setup, a loose(ish) crush (.050), and some rice hulls thrown in on the false bottom I can recirculate during the mash very quickly.
BUT...I have (until yesterday) throttled the ball valve down quite a bit. It circulates, but not enough to create a giant cone of grain (which I can do with the ball valve open all the way).
Well, I was taking readings yesterday and noticed that there was A LOT of variation in temperature throughout the mash and the temperature reading on the PID. Something was wrong and has been from the beginning.
Luckily I remembered the sage advice of a member of my brewclub (catt22). He recommended keeping your fittings big (check), your tubing big (check), and your recirculation as fast as possible (NOT check).
I've been throttling my recirculation because it was the only way I could avoid getting a vacuum in the mash. But even still I would pull a pretty good vacuum anywhere from 20-40 minutes into the mash. I know this because, again catt22 had the brilliant idea of installing a vacuum gauge on your MLT outlet. So I'd pull a vacuum and have to stir and unsettle the grain bed. Not ideal especially for step mashes and longer mashes.
Well, yesterday, my temperatures were off, I was starting to get a vacuum, and I was getting pissed. The PID said one temperature, my thermapen said another, and a 12" probe thermometer (from Thermoworks...the makers of the Thermapen) taking a reading from the bottom of the mash said another). A classic case of stratification. And it seems to be common (or at least expected some what) in RIMS & HERMS systems. Well, I don't want it. I want my mash to be 152F when I tell it to be 152F and I want the whole thing to be 152F, not just the outside or the inside or wherever. BUT...I'm not going to invest in a mash mixer which seems to be the only given solution for avoiding stratification.
Well, I finally figured out the problem AND more importantly, the solution. By laying the hose in the mash (even with the float attached to keep it from sinking into the grain), I was inadvertently causing the suction. And the slower recirculation was causing the stratification.
My hose placement was (gradually) creating an easy path for the wort to flow down around the sides where the wort was circulating. But it was not going through the middle. I had created a path of least resistance. This led to the stratification as the hotter wort from the bottom wasn't being evenly distributed because the grain bed in the middle wasn't getting the warmer wort.
Not only that, but I was losing the large surface area of the false bottom that allows lots of wort to flow through down to the diptube. I was draining through the grain, but really only through the sides causing the diptube to suck wort out, which was compacting the grain bed around the center meaning even less wort was going through that part of the mash...hence the vacuum. And the cycle continued.
What added to my frustration is that I know from tests that I can recirculate 10 gallons through my MLT without creating suction in 1min 45sec. That means that every 1min 45sec every ounce of wort in that mash should be able to pass the RTD giving me an accurate temperature reading and have a chance to be heated up appropriately without any risk of scorching (direct fire).
THE SOLUTION...After getting frustrated, I calmed myself down and channeled catt22.
I turned off the pump, stirred the mash up really well, gave it a couple minutes to settle, and (remembering what catt22 said) I opened that ball valve up for a very quick recirculation...BUT I DID NOT lay the hose in the mash. I held the hose...for 90 MINUTES (60min for mash 15min for heating up to mashout and 15min for mashout). The whole time I was moving the hose of returning wort over the top of the mash to ensure even distribution of the hot wort.
After that, I didn't get ANY suction AND within 5 minutes every single one of my thermometers were reading the exact same temperature. The top of the mash was the same temp as the middle, bottom, outside, inside, RTD, etc. ABSOLUTELY NO TEMPERATURE STRATIFICATION and all because I increased the flow and stood there holding that hose.
So...lots of info (for those that care). But here's my problem and I'm trying to figure out a solution. I (obviously) don't want to hold the hose during the mash. I added automation so I could keep my temps consistent and be able to walk away. So I'm trying to figure out a solution that will distribute wort evenly over the whole grain bed. But because it's the mash, the mechanism I use needs to allow grain particles through and needs to be big enough to allow the wort to drain out but NOT squirt or jet out so much that it creates the same problem as before.
Any ideas?
I use keggles so the MoreBeer sparge arm is out (and it's expensive)...and I think my flow rate would have it squirting as it shoots into the diverter plate. I've thought about making something out of CPVC or perhaps using a stainless collander that hangs inside the keggle, but I'm not sure. Let me know your thoughts and if my experience helps you.
