Emergency Decoction?

[Genjin]

So I am brewing a bitter tonight with only Munich malt. I am using 8.5# Munich for a 4 gallon batch and I am using my new mash tun for the first time. I missed my mash temp by 10F leaving me at 140 instead of 150. I think that I hadn't accounted for the temp loss in transferring the hot liquor over to the mash tun as before I had simply used my brew kettle and insulation for BIAB.

I got cocky after watching the Brewing TV episode on decoction mashing. So I let it rest at 140 for about 20 min and then pulled about 5 cups of grain and a bit of liquid out after using a brewing calculator and boiled it. Then I added back to the mash.

Was this a stupid way to raise the mash temp? What are some possible dangers of doing a decoction without really knowing what you are doing?

 

[digitalhifi]

I'd say you should be fine. This is pretty standard practice for me on my decoction lager brewdays when I miss my mash temp by 5-6 degrees or so. I would be less worried if you were using a grain with a higher diastatic power (more enzymes to convert itself) like pilser or 2-row. Really the only danger I can see is by boiling a portion of the wort you have reduced the amount of total enzymes you have for your sachrification conversion. But by how much is anybody's guess.

 

[mjohnson]

My understanding is that most of the enzymes will be in the liquid part of the mash, so you did no harm. It'll probably be the best bitter you've ever made. Sounds to me like a really great way of adjusting your mash temp. Bravo for the quick thinking.

 

[ReverseApacheMaster]

The only thing I would point out is that you probably hit the right temperatures and didn't know it. When you add strike water you need to stir for several minutes before checking the temperature. If it's off, stir more and check again. A lot of times it takes a while for the temperature to even out.

If you didn't preheat the mash tun then you might have actually been under the correct temperature.

 

[Genjin]

Well, I was a few points low on my OG, but that could have been from a number of things (first time on new system, used low diastatic malt, relatively short mash - 60min, etc.) The decoction smelled awesome, can't wait till I can lager and do a proper decoction. Next time I use 100% Munich I will do a longer mash as well.

Thanks for the feedback.

 

[Malticulous]

I would have done either a decoction or taken some of the sparge for an infusion.

I like to heat my strike five or more degrees higher than I need and let it cool in the MLT with lit on. When it's at temp (I may add some ice to get it there) I dough in.

 

[ArcticBear]

If you didn't preheat the mash tun then you might have actually been under the correct temperature.

this was my thought. I always throw hot water into my mash tun and let it sit and heat the tun (home made cooler mash tun) until I'm just about ready to mash in and I always hit temp within a degree or two. If you don't factor in the cooling properties of a cold mash tun on your room temp grains and strike water you'll always miss target temp by a few degrees

 

[Genjin]

this was my thought. I always throw hot water into my mash tun and let it sit and heat the tun (home made cooler mash tun) until I'm just about ready to mash in and I always hit temp within a degree or two. If you don't factor in the cooling properties of a cold mash tun on your room temp grains and strike water you'll always miss target temp by a few degrees

This is what happened. Cold mash tun. I will definitely warm it up first, thanks!

 

[ArcticBear]

This is what happened. Cold mash tun. I will definitely warm it up first, thanks!

 

[mjohnson]

If you use beersmith - you can put in the temp of the tun and it will correct for the heat loss. I've stopped pre-heating my tun because it works so well.