RIMS recirculation rate, scorching, and scorched deposits

[Cajun_McChicken]

So I was using my new RIMS setup for the second time on a robust porter with 8oz flaked barley and I got a stuck mash. After taking great pains to free it up I must have set the pump to recirculate too slow and I brunt the heck out of the wort (kinda tasted like an extra scorched cup of Starbucks coffee). This also left me with crazy levels of brunt stuff on my heating element which has MOSTLY come off after over a week of overnight oxyclean soaks and vigorous scrubbing.
My questions:
1. What are your tricks for avoiding a stuck mash during continuous recirculation?
2. Do I need to get every last speck of the burnt stuff off of my heating element in order for future batches to not have that burnt taste?

Thanks!

 

[helibrewer]

With anything flaked, use rice hulls, .5-1lb in the mash. Use a low watt density element and operate it with a PID, at least that way there is something to turn the element off when temps rise too much.

I went to a gravity feed MLT and use a grant, that way there is never pump vacuum on my MLT. Just be sure to start your flow very slow, and don't energize your RIMs until you are sure you have good circulation. I have a cut-off switch on my RIMs so if I do get any issue with recirc I can kill power to the RIMs easily and quickly.

 

[atoughram]

I scorched a batch last week because I had the recirc rate too low. Live and learn I guess, I think I'm going to throw out 11 gallons of Hefe. It tasted smoky. I think I'll start adding rice hulls just in case. cheap insurance.

On your second question, every last speck?? Nah.. I took a wire brush to mine and cleaned it off, but there is a lot of gunk left on it. If you can get the gunk off, but all means do it, but I think you'll be ok. My element is stainless, so I might try some oven cleaner on it over night.

 

[NuttyProf21]

Are you guys using ULWD elements?

 

[atoughram]

Mine is LWD but only 2KW.

 

[augiedoggy]

Mine is LWD but only 2KW.

Still hotter direct contact with the wort as far as I understand...

 

[atoughram]

Still hotter direct contact with the wort as far as I understand...

Maybe so - but it makes good beer

 

[cfrazier77]

A rule of thumb that I was told and that works for me is this. For everything that does not have a hull, flaked or wheat, add rice hulls at the same volume. 2 cups of flaked corn = at least 2 cups of rice hulls. Rice hulls are cheap and to easy not to use.

 

[bbrim]

What type of manifold/false bottom do you use? I have a copper manifold that is square with an extra tube running down the middle. I use flaked grains frequently, with only minimal rice hulls, and I'm able to run my RIMS pretty fast. I run a bit faster than 1 qt/min. I do let my mash settle for about 5 minutes before I turn on my pump and let that run an additional 3-5 minutes before turning on my heating element.

 

[atoughram]

I run a bit faster than 1 qt/min.

I'd better be running at 2-3 qt/min if not faster. Here's the bottom of my MLT

The upper manifold is a Loc-Line (Not in the picture)

 

[augiedoggy]

Maybe so - but it makes good beer

yes but at the cost of scorching the wort more easily... hence the topic of this thread.. Im pretty sure that the wort is less likely to burn against the surface of the ULWD elelments for the same reason they fight off lime and scale deposits in a hot water tank...

 

[Poobah58]

How thick is your mash? Use at least 1.5 qts or water per pound of grain. Use ULWD elements regardless of wattage in a RIMS. A LWD 2000W element at 120v can still get pretty hot. BTW, You can't run the wort too fast or you will collapse the false bottom if stuck. I speak from experience!

 

[Cajun_McChicken]

Thanks for the tips everybody! I replaced my HWD element with an ULWD version (5500W on a 120v circuit instead of 1500W) and ill make sure to throw in some rice hulls so I can keep my recirculation rate up.