RIMS exit temp vs mash temp

[Dcpcooks]

What are the odds that my probe is reading higher than actual temps? I'll do an ice water test soon

Your better off calibrating @150 with a good thermometer. If your mashing at 152 then 32 degrees is 120 degrees away. If you check it against a boil your 60 degrees away. Your really only concerned with a range of 113 to 170 with most of your time spent around 144-158. So that what your calibrating too. If your off by 2% your going to be ok but 2% of 120 is a lot more of a spread.

 

[schematix]

That comment about waiting 10 minutes before starting recirculation is interesting. I start recirculation as soon as the grain is doughed in since I want to fully mix all the water with the bed and make sure the wort temperature is more uniform.

I've noted a similar issue before where if i immediately started to recirculate i'd always end up with a stuck mash. No amount of stirring ever seemed to fix it. I'd always have to dump the mash tun out and blast out the false bottom. If i waited 10 minutes and started slow it would settle the grain bed and start to clear within a few minutes.

More recently i've been underletting the mash initially, targeting 131F. The dough-in procedure takes about 12 minutes, and as soon as it's done, i stir it, put on the mash cap, and crank up to the first beta rest right away. In my 15G boiler maker G1 mash tun i recirculate at 1.5GPM. Even more recently i tried to maximize the amount of grain in the tun and above about 28 lbs I can't recirc above 0.9-1 GPM without sticking it.

 

[dyqik]

I'm underletting about as fast as a 24V little tan pump will let me, and I can immediately start recirculating at about 20% of max flow rate. I bring that up to fully open in about ten minutes.

This is with conditioned grain and a domed false bottom. If there's wheat in the mix, I'll throw a big scoop of rice hulls in before putting the grain in and underletting.

 

[logdrum]

This thread has been quite illuminating [emoji106]🏼

 

[cod3ck]

My tun has a manometer tube ported into the bottom so that I can monitor the head at the bottom of the grain bed. With that instrument, I have found that all mashes have low permeability initially and its permeability increases during the mash. I have also found that I don't create a stuck mash if I limit the head drawdown to about the bottom of the bed. If you don't have a manometer in your tun and you try to run the pump at too high a rate, you can pull a great deal of negative pressure on the bottom of the bed and that can compact the bed. Wide open is NOT a good idea in RIMS and HERMS. You should have a way to monitor the head at the bottom of the bed.

Just to be clear, the manometer is purely to monitor if the grain bed is compacting and preventing flow correct? I'm thinking of doing something similar, but using a vacuum gauge instead so I don't have to buy a more expensive false bottom or bother punching more holes in my keggle...

 

[Dcpcooks]

Just the be clear, the manometer is purely to monitor if the grain bed is compacting and preventing flow correct? I'm thinking of doing something similar, but using a vacuum gauge instead so I don't have to buy a more expensive false bottom or bother punching more holes in my keggle...

Yes a manometer measures the relative vacuum created under the mash bed. I'm not sure how you'd get a vacuum gauge to measure that unless it's placed under the mash. I sight gauge will show you the same thing to a certain extent.

 

[logdrum]

As a follow up, I programmed an offset into the EZ Boil & it holds the (water) temp rock steady. Looking forward to the first RIMS brew!

 

[BrunDog]

Just the be clear, the manometer is purely to monitor if the grain bed is compacting and preventing flow correct? I'm thinking of doing something similar, but using a vacuum gauge instead so I don't have to buy a more expensive false bottom or bother punching more holes in my keggle...

I see this same effect with both my sight glass and my electronic volume measurement (via hydrostatic pressure sensor). Makes having a sight glass worthwhile.

 

[cod3ck]

Yes a manometer measures the relative vacuum created under the mash bed. I'm not sure how you'd get a vacuum gauge to measure that unless it's placed under the mash. I sight gauge will show you the same thing to a certain extent.

Correct-- the vacuum gauge will go inline just upstream of the wort outlet flow valve on my bottom draining keggle. We'll see how it works in reality, but the idea is any suction pressure that would occur between the pump and a compressed grain bed, should display on the gauge indicating a vacuum is occurring and needs to be corrected for.

For now, I'm trying to avoid a sight gauge based on reasons already mentioned, and it's just one more thing to clean...

Still waiting on parts, but once it's setup I'll post pictures if anyone's curious.

 

[cod3ck]

I'm underletting about as fast as a 24V little tan pump will let me, and I can immediately start recirculating at about 20% of max flow rate. I bring that up to fully open in about ten minutes.

This is with conditioned grain and a domed false bottom. If there's wheat in the mix, I'll throw a big scoop of rice hulls in before putting the grain in and underletting.

Those tan pumps max out at just over 1.5 gpm correct?

If this is the case I way overkilled my first RIMS run with a chugger pump! No wonder I ended up with a stuck mash at 7 gpm [emoji13]

 

[day_trippr]

Right - little pump wide open = big pump throttled down
fwiw at peak recirculation I'm running around 2 gpm. Using an 815...

Cheers!

 

[schematix]

good post on relatively inexpensive flow meter... https://www.homebrewtalk.com/showpost.php?p=7832702&postcount=14

it's been worth every penny.

 

[BrunDog]

Here's mine!

Sorry... had to do it!

 

[BrunDog]

Remember, all the enzymes are in the wort...not the grain bed. Bringing the wort to temperature is the objective. Bringing the grain bed to temperature is only a result.

Wow... I did not know that! I thought they were in the kernels. I assume then, that they flow out into the wort easily, because they aren't in the mashing water at the start?

 

[processhead]

Wow... I did not know that! I thought they were in the kernels. I assume then, that they flow out into the wort easily, because they aren't in the mashing water at the start?

They start out in the kernel. Water and raised temperature activate them and they they go into solution along with everything else that can dissolve in water.

 

[BrunDog]

Been brewing a while, but still appreciate the learning.

 

[dyqik]

Double post, thanks to the mobile app which always gives errors when posting.

 

[dyqik]

Those tan pumps max out at just over 1.5 gpm correct?

No, 12 liters per minute/3.5 GPM with the 24 V version.

 

[cod3ck]

good post on relatively inexpensive flow meter... https://www.homebrewtalk.com/showpost.php?p=7832702&postcount=14

it's been worth every penny.

Sweet!!

Hmmm... would a vacuum gauge AND a flow meter be overkill? [emoji57]

 

[dyqik]

A sight glass is a perfectly good vacuum gauge for RIMS. And you probably want one of those anyway. You just adjust the flow so that there is still liquid in the sight glass.

 

[SplitHops]

OK, so this is just from a preliminary water test with my EZ Boil controller, but when I ran a recirculating trial (tap water in my Spike mash tun, to a chugger, through a RIMS Rocket, back to mash tun) the temp probe at the exit of the RIMS Rocket read 133ºF (my set point) but the water in the mash tun (measured with a Thermapen) was at 122.xºF. I am a total RIMS newby, so I'm curious if this behavior will carry over to a real life mash, or will the thermal mass of the grains alleviate the offset? Thanks in advance!

I ran with a RIMS tube same principal as the ROCKET for some time and contrary to what some say on this post, it is for heating as well. The rims tube is for recirculating and what good would it be if it can't heat during re-circulation?

I have since switched over to a HERMS coil system in a 25 gal. Stout kettle. During re circulation I found that I lose form the out feed on the herms coil to the mash kettle about 10 deg. The best part of this would be I never have a chance of scorching my wort over an exposed heating element as with the RIMS system. You may be simply experiencing a temperature loss in lines from your rims to the kettle, I know it sounds impossible but it happens.

 

[helibrewer]

good post on relatively inexpensive flow meter... https://www.homebrewtalk.com/showpost.php?p=7832702&postcount=14

it's been worth every penny.

I use this one: Flowmeter. It is 1/2" thread and screws right onto the output of my pump head.

 

[doug293cz]

I use this one: Flowmeter. It is 1/2" thread and screws right onto the output of my pump head.

Have you run boiling wort thru this flowmeter, or only mash temp wort? Concerned about suitability for recirculating eBIAB.

Brew on

 

[schematix]

Have you run boiling wort thru this flowmeter, or only mash temp wort? Concerned about suitability for recirculating eBIAB.

Brew on

Very good point.... most rotameters out there, especially for 'water', are not rated for very high temps.

The one i use is rated for mash temps, but not boiling. You can get them rated higher but they are stoopid expensive.

 

[augiedoggy]

Those tan pumps max out at just over 1.5 gpm correct?

If this is the case I way overkilled my first RIMS run with a chugger pump! No wonder I ended up with a stuck mash at 7 gpm [emoji13]

the 12v ones pump just over 2 gpm the 24v ones pump just over 3 gpm.. I run my system at 1.5-1.8 gpm (on the flowmeter) when recircing through my rims with a 24v pump pulling through the grainbed.

And YES those big pumps are way overkill for using a rims in homebrewing scererios.

 

[augiedoggy]

That comment about waiting 10 minutes before starting recirculation is interesting. I start recirculation as soon as the grain is doughed in since I want to fully mix all the water with the bed and make sure the wort temperature is more uniform.

My tun has a manometer tube ported into the bottom so that I can monitor the head at the bottom of the grain bed. With that instrument, I have found that all mashes have low permeability initially and its permeability increases during the mash. I have also found that I don't create a stuck mash if I limit the head drawdown to about the bottom of the bed. If you don't have a manometer in your tun and you try to run the pump at too high a rate, you can pull a great deal of negative pressure on the bottom of the bed and that can compact the bed. Wide open is NOT a good idea in RIMS and HERMS. You should have a way to monitor the head at the bottom of the bed.

I have found that quite a bit of conversion already takes place by the 15 minute mark so I try to dough in as close as possible..

 

[NdO]

I see this same effect with both my sight glass and my electronic volume measurement (via hydrostatic pressure sensor). Makes having a sight glass worthwhile.

Could you link the model of your eletronic volume measurement? I searched it on your rig topic, but couldn't find.

Thanks in advance!

 

[BrunDog]

Could you link the model of your eletronic volume measurement? I searched it on your rig topic, but couldn't find.

Thanks in advance!

Here is the link: https://www.homebrewtalk.com/showpost.php?p=7961332&postcount=255

The sensor is: https://www.digikey.com/product-detail/en/panasonic-electronic-components/ADP51B61/P17123-ND/3244557.

 

[NdO]

Here is the link: https://www.homebrewtalk.com/showpost.php?p=7961332&postcount=255

The sensor is: https://www.digikey.com/product-detail/en/panasonic-electronic-components/ADP51B61/P17123-ND/3244557.

What about this sensor, don't you use it anymore?

 

[BrunDog]

No. While this sensor was great and worked well, it was a binary output (On/Off) and required manual positioning. The variable sensor can read the volume at any level. I had to use the binary sensor with the previous control system, but my current one has the flexibility to read analog values.