I have tried a rims system and find the re-circulation compacts the grain bed, decreasing the flow, resulting in overheating in the heater and diminished heating in the mash. apparently a gas fired and gas valve controlled temperature regulator is the way to go, but out of my price range at this time.
could I use a cooling coil and my rims heater in a gott 10gal mash tun to stabilize the temp? does anyone think I would be able to achieve multiple temperatures in a reasonable amount of time.
Thanks
PS should I think of using glycol in the rims and coils
[quote=“tbone4192”]I have tried a rims system and find the re-circulation compacts the grain bed, decreasing the flow, resulting in overheating in the heater and diminished heating in the mash. apparently a gas fired and gas valve controlled temperature regulator is the way to go, but out of my price range at this time.
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I don’t know if automated temperature control would help, but to achieve reasonable mash temp ramps requires that you recirculate a significant amount of wort. To achieve this, keeping the grain bed from compacting is a must. Some straining systems work better than others, but throttling the pump at the proper level is important to keeping the mash flowing.
What I found is that when you start to recirculate, start really slowing for at least 5 minutes, and very slowly increase the flow rate overt time. This helps set the mash loose enough to keep it flowing. Also, it may be that there is a certain maximum flow rate your system can achieve without sticking the mash. Large diameter piping combined with careful mash recirculation rate management helps keep flows high while reducing the chance of mash compaction.
It’s a tricky balance that can take some time to figure out, but if you compact your mash you can always stir it up and start recirculation over more slowly.
I assume that the OP does not have a manometer (sight glass) that reads the pressure at the bottom of the grain bed. As a RIMS user for almost 15 years, I can assure readers that it is very important to monitor and adjust the flow rate through the bed to avoid excessive head loss through the bed. If a user tries to pump at a pump’s full flow rate, it is possible to create a very strong hydraulic force that can ‘compact’ the grain bed. In essence, the bed is compressed to the point that the voids between grain particles collapse and there is nowhere for the wort to pass.
Without a manometer ported into the bottom of the grain bed, a user would have no idea that they are over-pumping the bed and creating that excessive hydraulic force.
The permeability of the grain bed does change during the course of a mash. It is initially relatively low and I have to significantly throttle the pump to avoid compacting the bed. As the extraction and conversion progresses in the mash, the permeability improves and I can open up the throttling valve. I never have stuck mashes.
The other thing that a RIMS user HAS to include in their system is a PID so that the wort is not overheated. If the wort is overheated at ANY time while passing through the circuit, that will quickly denature the enzymes. You will end up with starchy wort that does not convert. Be sure that the temperature sensor for the PID is located immediately downstream of the wort heating point so that the PID can better avoid that overheating problem. The temperature of the wort matters more than the temperature of the mash bed. Don’t overheat the wort in pursuit of producing a certain mash bed temperature.
I’ve read about this differential pressure.
http://brewlikeapro.net/lautering.html
Do you actually have pressure gauges on your mash tun? If so which ones are you using and how?
I’ve read about this differential pressure.
http://brewlikeapro.net/lautering.html
Do you actually have pressure gauges on your mash tun? If so which ones are you using and how?[/quote]
No, you don’t need anything as elaborate as what Dave Miller shows on his page. All you need is a single sight glass plumbed into the underside of the mash tun. It can be as simple as putting a Tee into the outlet pipe from the tun and putting a clear tube on the Tee (vertically). The top of the tube is open to the atmosphere. When the pump is not operating, the water level in the sight glass is equal to the level in the tun. When you turn on the pump and start drawing water through the bed, the level in the sight glass will drop. I find that keeping the water level in the sight glass about an inch above the bottom of the tun is a good compromise on flow and avoiding bed compaction. Obviously, if you pump too hard, the pump will draw air through the sight glass (not a good thing).
Do you have a Blichmann kettle, Martin? Their sight glass “bottim inlet” is at the bottom of the grain bed, but not beneath the false bottom (see http://cdn.homebrewtalk.com/attachments … inside.jpg ).
Is it sufficient to be at the bottom of the grain bed, or are you stating that the bottom inlet to the sight glass needs to be below the false bottom, or even further, on the bottom of the kettle itself?
It sounds like you’re considering putting the immersion chiller coil in the mash, right? I tried it many years ago. It required lots of stirring, and having the coil in the mash made stirring difficult.
Maybe a larger false bottom or slotted manifold would allow the wort to drain more easily - something like Denny’s system (dennybrew.com).
Andrew, the Blichman arrangement is not ideal. But it is close to it. Having the port inlet below the false bottom would be ideal and should represent the total head loss across the grain bed.
You could always use a grant and gravity feed wort into it, then adjust the pump to maintain the level in the grant. You can use the electric element in the grant. This is how I was going to go if I ever get around to trying RIMS.
