RIMS - Mashout

[Bobby_M]

I was able to step from 122 to 158 over 20 minutes with a direct fired RIMS (10 gallon recipe). Jamil's Belgian Wit directions say to do it in 15 minutes. If you can do 20 minutes through a RIMS, that would be fine with me.

The point I was trying to make is that the faster you can flow through the RIMS tube, the more wattage you can make use of. Hypothetically if you flow 2gpm and your wattage only gets you a 5F temp rise between the in/out of the RIMS, doubling the wattage conceivably gets you a 10F rise instead. It wouldn't help you reach mashout in half the time, but it has to be worth the effort. No matter what, I'd want the output of my RIMS to be at my set temp at whatever my max flow rate was.

This would be the ideal situation but small departures from it wouldn't be that big of a deal either.

 

[JVD_X]

We could increase the pipe size from the usual 1/2" to [a larger size] to increase the flow rate. I am also interested if a low-density element of identical wattage as a high density element heats at different rates because of exposed area.

 

[The Pol]

Compare the BTU output of a burner on a direct fired unit, to the BTU of a heating element in a RIMS heater.

5500W = approx. 19,000 BTU... how many BTUs is your burner?

So if you had THREE 5500W elements running at 5500W each, you would have just under 60k BTU.

Typical RIMS heating element:

1500W = approx. 5,200 BTU

 

[Joshua618]

It is relieving to hear that I am not the only one with slow ramp-up times to mash out on a RIMS.

What water/grist ratios are you guys using on a RIMS system?

 

[JVD_X]

I have been using 1.25 but recently moved up to 2.0 because of a recent thread. I actually saw a decrease in my efficiency with a thinner mash, which leads me to believe that - at least in my personal RIMS system - a thinner mash doesn't work as well as a thicker mash. I'm still confused as to why it is an issue moving from 150 to 170 over 20 minutes rather than 10. If the conversion is done, the conversion is done right?

 

[The Pol]

I have been using 1.25 but recently moved up to 2.0 because of a recent thread. I actually saw a decrease in my efficiency with a thinner mash, which leads me to believe that - at least in my personal RIMS system - a thinner mash doesn't work as well as a thicker mash. I'm still confused as to why it is an issue moving from 150 to 170 over 20 minutes rather than 10. If the conversion is done, the conversion is done right?

I dont think anyone said that there was a problem with ramping up to mashout over 20 mins... it just takes a long time, lengthening the brew day. It shouldnt affect the beer in any way, I dont think that was the point of the thread.

Now in a previous post we were talking about ramping up from say 122-158... that could be a problem, because conversion is not complete and you will be converting sugars for a long period during the ramp, instead of at your target temp.

 

[JVD_X]

I recently built a RIMS with a PID to contol it . I have a couple of questions about mashout. I am using a keg with a false bottom as a MLT and a March pump. The heat exchanger is a 4500W heating element running on 110 VAC. After recirculating the mash for one hour I would like to raise the temperature of the mash to 168-170 before sparging. After the recirculating, I turned up the temperature on the PID and it took a long time to get the actual mash temperature to rise. This was on a 5 gallon batch. I have a thermometer measuring the temperature in the MLT. The sensor for the PID is located immediately after the heating element, before returning to the MLT.

Should I set the PID to 168-170 or higher?

Would reducing the flow through the heat exchanger heat the water better? Should I leave the valves wide open during this step?

Any suggestions to get the RIMS to mashout better would be greatly appreciated. Thanks.

It just occurred to me... did you run the autocalibration routine on the PID? This might explain you long ramp times.

 

[Joshua618]

Yes. I ran the auto tune on my PID.

 

[Bobby_M]

You could argue that step mashing doesn't really require instantaneous adjustments anyway. This is an organic thing where activation of the enzymes that favor the next temp range and the denaturing of the previous has an overlap anyway. You could plan your ramp up to start a little sooner and you can achieve repeatability. This is especially true due to lower temp enzymes being slower.

 

[The Pol]

I would have to assume though that if it takes 20 minutes to ramp to mashout temps... so 153-168F, that it would take nearly 40 minutes to ramp from a protein rest to sacc. rest. That to me seems like it would be very long. It would no longer be a step mash, but simply a ramp mash.

Again, if you have a direct fired RIMS you have more capability than the guy heating with 5,000 BTU in a little RIMS heater. You have what, 60k or 100k BTU at your disposal? Of course it takes him 20 minutes to mash out, the math supports it, it has nothing to do with his PID or any other variable. You have a finite ammount of heat introduced and a HUGE thermal mass to change.

How many BTU is a stove top? 9,000? How many of you can reach a boil on a stove top with 5 gallons? Now take his 5,000 BTU in his RIMS heater and try increasing the temp of a 7 gallon mash.

Direct fire, or infusion is about the only way to have a short step time. Though, back to the OP, 20 minutes is normal with 5,000 BTU at your disposal and should not affect the beer.

 

[Bobby_M]

There's no way you can apply 60Kbtu to a mash tun. My burners are 60-70k but I run them as low as possible which I'd have to guess is 30k. However, a flame of 30k translates to more like 20k in effective btu due to all the heat that licks up the side. I suspect an element surrounded by liquid is getting you more like 95% efficiency. I'm not suggesting that an element can be just as fast but if you have the circulation flow at max and the temp coming out of the HEX is at set temp, you have a much better shot at it.

The other thing that I'm thinking is that even at 1gpm, you'd cycle the whole liquid volume of the mash through the HEX at least twice in 10 minutes and expose most of the enzymes to 168F short short periods even if they cool back off in the mashtun. How long does it take to denature at that temp?