Complete insanity RIMS Recirculation

[kvnc]

So I was step mashing using a RIMS system. Took the beer from protein rest at 131 for 20 min to 145 for initial sac rest. let it sit at 145 w/ recirculation on for 25 min. Checked the wort, everything was pretty good so far, i was seeing 1.055 gravity and color was nice, if not slightly paler than i expected with my grain bill. Anyways, I stepped up again to 154 held for 35 min, came back to do a mash out and color was substantially darker, like a 14srm from like a 4srm. Gravity was higher now too, like a 1.075. My initial thoughts were that the wort got scorched somehow, but Ive 1: never had that issue with this system before and 2: the wort didn't taste burned at all. 3: flow rate was fine, did not slow down or stop. When I was cleaning out the spent grains after, the actual grains look pretty dark and sort of like not as vibrant as Im use to seeing. They just looked weird. Anyways, I'm continuing on fermenting this stuff because it seems to taste okay, but I just wanted your opinions as to what would cause the significant darkening of the mash. Was originally targeting like a 6.5 srm. Its got to be the RIMS system right? As the gravity increased in the mash, more caramelization could have occurred over the element in the RIMS maybe? Does hot side aeration exist? It sort of has that brown oxidized color twinge to it. Any one else ever experience this/ know what is going on? I appreciate the help.

 

[RPh_Guy]

Oxidation doesn't cause that much darkening in the mash; it had to be some kind of caramelization or scorching from the RIMS. Did you have a look at the element before cleaning?

The mash certainly can and does fully oxidize unless you follow a series of steps to avoid it know as low oxygen brewing. Oxidation is "normal" for most brewers, and it's what you're used to seeing at baseline.

Welcome to HBT!

 

[kvnc]

Thanks, thats kind of what I figured. It was just so weird as Ive never had it happen on this system before, so I had to ask.

 

[augiedoggy]

If you had scorching you would know because the rims element would have a charred buildup on it. I recently learned that step mashing with some adjuncts like rye can cause this even with an ULWD element and good flow.(The result was the unfortunate dumping of 3bbls of beer ). this is due to a geletian like substance which develops during the step mashing process at a certain temp point which easily sticks to the element.
As long as your not using a sparge arm to shower the wort over your grainbed your oxidation contribution from a rims should be relatively minimal. Some people are using this type of setup with sprinkling arms because of the bling factor and dont seem to care or realize it actually effects the beer negatively as much more aeration is occuring which diminishes the flavor profile through rapid oxidation.