hit 180! Are grains cooked?

I did my first AG brew the other day. I mashed in my 7.5 gal kettle using a giant fine mesh bag. I had trouble kepping the temps controlled for a 2 step mash though. I was able to keep the temp @ 130 for thirty min. but when I tried to bump the heat up to 152 it jumped to 180+ in just a couple min. I took it off the heat and let it sit until the temp dropped back down to 150, then kept it there for the remainder of the mash. My OG was so low that i don't think I got a good starch conversion. My question is, if the temp hits 178-180 are the grains cooked? Will conversion start again if the temp drops?

The higher heat will make more un-fermentables sugars, you'll proboly have a heavy bodied beer. But the UF's would still show in the gravity.

There is an alternative to infusion mashing like you did, it is called "decoction mashing". In decoction, you actually boil 40% of your grains, and add it to the cool grains to raise the temp to mash. I'm sure your "creative surprise" caused a somewhat lower efficiency, but it's not terminal.

How did you sparge? (wash the sugar from the grains?). My guess is you left lots of sugars behind by not washing the grains properly.

180F is more than the conversion enzymes can handle. If you had added cold water immediately, conversion might have restarted.

When you are heating a mash, turn the flame on for 45-60 seconds. Then shut it off, stir gently. Repeat as necessary. It's slow, but safe.

The 2 previous posts explain what could have happened:

- insufficient sparging through the use of a grain-bag. When I did parial mashes and sparged with a grain-bag, I had efficiencies of about 40%. Normally you should get 70-80% when doing AG.

- The mash enzymes are not able to hande 180F for an extended amount of time. Especially the beta amylase (Maltose producer) would have suffered significantly. I assume that you didn't do an idodine test to check for completed starch conversion. By doing so you can determine if the enzymes are actually active or not.

Just keep lots of DME handy to fix your first attemts on AG in case something goes wrong and your efficiency is way off

Kai

Thanks for the tip guys. I thinkd I should just get myslef a couple mash tuns. Trying to mash and sparge in the kettle proved to be more work and even poorer results. She's running strong in primary though, putting out some good head on top, and she smells nice too. ; ) We'll see how she turns out.