max element size?

[Merleti]

What is the max element size you can use on a rims tube without scorching the wort? I making a BIAB system that has a rims tube 1 1/2" with and a pump at 80 gph. I make 5-6 gal batches. Thanks for the advice.

 

[jeffmeh]

Unfortunately, I have no idea. I'm curious though. Why do you want a RIMS tube for e-BIAB? RIMS is a method to avoid direct-firing in the mash tun where the mash will be in contact with the element. For e-BIAB, the element is normally below the mash with water volume in between, so there is no direct contact between the mash and the element. Am I missing something?

 

[kwadric]

Scorching is more complicated than a power rating on an element. Most people look at power density: the power on the element divided by its surface area. The common target is low watt density (LWD element) which is 50 watts per square inch. These elements typically either fold back or ripple. I have not heard of anyone scorching wort with one of these LWD elements, but it could be possible. I use a LWD 4.5kW element in my system. I bought the element at Home Depot.

Some other factors that might influence scorching include: how much heat your system loses while recirculating, how fast you can run your pump without compacting your grain bed, if your system is 110V or 220V, and if you need to step mash.

 

[Merleti]

Maybe I'm thinking about it all wrong or using the wrong terminology?

jeffmeh I was going to circulate the wort through the tube that has a heater element in it and then back over the grains in a cooler. This way I could do step mashing if needed and have better efficiency having it flow through the grains.

kwadric the heater will be in a 1.5 inch tube with 80 gph of wort flowing over it.

 

[jeffmeh]

No worries. Terminology-wise, that would not be BIAB, but more like a traditional RIMS system. It all makes good beer.

 

[kwadric]

If you are going to order your element online, I think plumbers supply has some 5500 kW lwd elements. If you are going to a store, check out the Home Depot web page. They have a 4.5 kW lwd (50 watts per square inch) that has worked well for me. I do a mash out most brews (up to 170F) and it takes 5 min for me to get a near 170 with a med-low flow rate.

Check out some HBT threads about RIMs step mashing and compacting the grain bed (maybe search RIMs and a grant) if you haven't already. Most people throttle the output of their pump down to avoid compacting their grain bed. But the faster you recirculate, the faster your step mash is. How fast you can recirculate with out compacting the grain bed depends on a lot of factors

 

[jCOSbrew]

The advantage of the element in the kettle for eBIAB is that the same element heats the strike water, controls the mash temp (if necessary) and controls the boil.

The rims tube could maintain the mash temp and possibly increase temp for mash out.

 

[Merleti]

Thank you all for the input. I appreciate it. I noticed the ULD's are longer than my original plans. I decided not to worry so much on maxing the size, but go with what will fit best in the tube I am using. I also remembered it it for my mash and the water volume will be lower than I planned for. Thank you all again!

 

[kwadric]

And to maintain mash temp, you don't needs much power. My 4.5kW element runs at about 10% to 20% duty cycle. The higher power helps with increasing mash temps, which is fun, but not really essential.