[Hokerer]

I use this one as my certified "master" thermometer, not bad for $6.50...

http://cynmar.com/item_detail.aspx?ItemCode=09601951

[oscarvan]

Well....I hit my gravity dead on..... so I got sugars. What kind of sugars I don't know.... We'll see how it attenuates. As I said in my oriinal post, it may or may not have gotten to 170 depending on which thermometer is right.....I have a gut feeling we're going to be OK here.

Meanwhile I will order one of those lollipop thermometers and make calibration tables for the various thermometers.

The good news is that I hit all my volumes dead on today.

Learning is taking place.

I appreciate all the help.

Oscar.

[denny]

Meanwhile I will order one of those lollipop thermometers and make calibration tables for the various thermometers.

I like to use the bimetal dial thermometers for brewing since they're so easy to adjust when you calibrate them.  Then you need to keep referring to a table.  And be sure to calibrate them in the mash temp range.

[Kaiser]

Those activity graphs are great, what is the original source for the data? 

The PDF seems to be gone from the link at which I found this. I'll have to check if I have a copy at home.

Kai

[euge]

We're talking a few minutes here. Having the conflict I went with the hottest temp and stirred the mash lid off until it came down, but I may in fact be too cool now.

I REALLY need some decent thermometers. I can't control what I can't measure accurately....these $7 dial thermometers are toys.

Anyone have a source for accurate tools?

I'm extremely pleased with my Superfast Splashproof Thermapen which is also NIST certified. A little pricey but it gives me reads in seconds.

Oscar if you keep a bit of ice handy, a handful can drop the mash a couple degrees in those panicky first moments.

[denny]

Those are great, Euge.  I'm trying to justify the price....hmmm, my birthday's in a couple weeks.....

[oscarvan]

And be sure to calibrate them in the mash temp range.

Good idea!

Oscar if you keep a bit of ice handy, a handful can drop the mash a couple degrees in those panicky first moments.

Another good idea..... However, as I am getting my system dialed in I am figuring out that there is very little heat loss from HLT to MLT...... so instead of going with 10º I will go with 5º which gives me a greater margin of error on the 170º and gets me closer to the target.

A little better every time.

[tom]

Once enzymes are denatured it is irreversible.

That is true for some proteins, but certainly not for all.

Thanks for correcting me. Learn something new every day.
Reviewing enzymes it appears they were first described in brewers yeast. Once again beer has saved the world!

But I would think that the brewing literature would know if beta- and alpha amylase denaturization is reversible or not.

Brew on

[tubercle]

Once enzymes are denatured it is irreversible.

That is true for some proteins, but certainly not for all.

Thanks for correcting me. Learn something new every day.
Reviewing enzymes it appears they were first described in brewers yeast. Once again beer has saved the world!

But I would think that the brewing literature would know if beta- and alpha amylase denaturization is reversible or not.

Brew on

 
Betcha can't un-fry an egg

[tschmidlin]

Betcha can't un-fry an egg

Yeah, some proteins don't denature reversibly, eggs are a good example.  And to your point tom, the brewing literature might have the information, you're right.  But they might not have done the required experiments either, I really don't know.  Clearly the proteins are inactivated at higher temps, and just as clearly they are irreversibly denatured at some point before the fermentation or mash temp profiles would have little meaning.  But where is that point where they are irreversibly denatured?  Is it just in the boil, or is it some point before that, and if before that, when?  Like Kai said, there is a time/temp component, but I haven't seen any data from the right kind of experiment to determine the answer.

Anyway, I'll do some digging and see what I can find.

[tom]

Why don't we just let Kai do it?     

[bluesman]

Why don't we just let Kai do it?     

+1 

I have always thought that 168F was the ideal temp to stop all enzymatic activity. Key word is "stop" but as others have also indicated I'm not sure if that's irreversible or not. Sounds like some experimentation will be in order to get to the bottom of all of this. 

[denny]

Just so people have a point of reference on this, here's a great chart from How to Brew...

[tubercle]

So, according to tschmidlin, and I have no reason to not believe what he says - I respect his knowledge, if some of these enzymes re-nature what would be the effect of starting hot, say 170f, and letting the mash cool down to 150? Maybe stirring to help it get down over a reasonable period or just leaving the mash tun lid open. Wouldn't this be a better way to expose the grain to necessary temp (see Denny's chart) than holding at a set temps or ramping up through the temp ranges.

 Just drinking out loud....

[a10t2]

So, according to tschmidlin, and I have no reason to not believe what he says - I respect his knowledge, if some of these enzymes re-nature what would be the effect of starting hot, say 170f, and letting the mash cool down to 150?

I tried that once and it made a much less fermentable wort. One mash had rests at 144°F and 158°F, and the other started at 158°F and dropped to 144°F over the course of about an hour and a half. The control wort had about 65% RDF, and the other was about 45%. I don't have the notes with me.

Alpha amylase requires the beta amylase products to produce a reasonably fermentable wort. Doing it in reverse would be easier, but isn't really possible.