[morticaixavier]

So as I understand the process in a step mash with a lower sacc rest followed by a higher sacc rest (145 step to 154) you are going for a more fermentable wort but still with some body.

What would happen if you reversed that? mash in at 154 hold for say 15-30 minutes then stir temp down to 145 and hold again for 15-30 minutes. does the beta amylase work on the midlength sugars formed by the alpha amylase? or will you end up with a less fermentable wort as if you just mashed at 154 the whole time?

[dbeechum]

Your biggest problem would be the denaturing of the beta. Up in the 150's is where they start to unravel, turn into spaghetti and cease to function.

[rstansbu]

I think the issue you'll run into is that after holding at 154F for a while, some (not all) of your beta amylase enzymes will be denatured.  The extent will depend on how long you hold at the higher temperature, but you will have some beta amylase enzymes that will begin to go to work on the medium chain sugars the alpha amylase enzymes spit out.

That said, I don't think this is a particularly efficient way of step mashing.  The point is to start at the low temperature when the predominant activity is beta amylase.  You control the amount of simple sugars the enzymes are allowed to create by controlling the amount of time it spends there.  Then you ramp the temperature up to get the alpha amylase activity to kick up.  This step won't miraculously add body to your beer if you had a 90 minute rest at 147F, because it can't create longer chain sugars out of simple sugars.  But if you limit your time at 147F and then ramp it up, there are still lots of longer chain sugars remaining that it will break into other long to medium chain sugars.  I do this with a lof of my Belgian beers, and in my opinion, what you are diong is adding complexity to the beer by creating a range of fermentable sugars.

[James Lorden]

all the enzymes wouldn't be denatured but a lot would... it would need to be a longer rest OR you could throw in another couple of hand fulls of 6 row - tons of enzymes!

[denny]

all the enzymes wouldn't be denatured but a lot would... it would need to be a longer rest OR you could throw in another couple of hand fulls of 6 row - tons of enzymes!

These days, 6 row doesn't have much more diastatic power than 2 row.  I use 6 row for the flavor it gives, not because it's more effective at conversion.

[tom]

b-amylase chops maltose off the ends of the starches.  It would be more efficient for the a-amylase to break up the long chains which would give more "ends" for the b-amylase to work with.  And then let the b-amylase chop off the ends into maltose.

You can mash at 156 to mazimize the a-amylase and then add more grain to lower the temperature into the 140s to let the b-amylas do its thing.

[morticaixavier]

For the most part i only do single step mashes anyway. I was more interested in the discussion and it seems to be an interesting discussion. Now it makes me want to try it.

[dmtaylor]

To be perfectly honest, most of my batches follow a sort of "reverse step" mash process.  I say "step" in quotes because I don't really step it down, it just falls gradually.  I mean, if I want my average mash temperature to be 150 F (as is my standard for ~90% of my beers), then if I don't insulate the mash tun too much or stir occasionally (both true), and the mash initially hits around 153 F, I can make the temperature fall slowly down to around 146-147 F over the course of 40 to 60 minutes mash time, so I think there's plenty of both alpha and beta enzyme action going on during that whole time.  If the beta enzymes are denaturing, I don't care, because whatever's going on in that "reverse step" mash turns out tasting great in the final beer.  And I've saved myself a hell of a lot of effort compared to an old fashioned upward step mash.  I can and have done the same thing swinging from 156 F to 144 F.  Pretty darn similar results in the final beer if you ask me.  Bottom line is you're going to make pretty good beer no matter how much or how little effort you put into it, and what truly matters, *I* think, is the AVERAGE mash temperature over the course of the whole mash, not this one in the 140s versus this one in the upper 150s or whatever.  Take the average -- that's what you need to shoot for.

[tomsawyer]

I've said before that the temperature optima of the two amylases is backwards.

One way to circumvent this, is to do decoction mashing.  This way you get to step up the decoction portion to get more alpha activity smaller chains of starch, then you throw it back in with the unheated portion that still have beta activity.  If you use a cool enough initial rest then your decoction will still leave the mash at a beta-friendly temp.

[Kit B]

I've said before that the temperature optima of the two amylases is backwards.

What do you mean by "backwards"?

[hopfenundmalz]

I've said before that the temperature optima of the two amylases is backwards.

One way to circumvent this, is to do decoction mashing.  This way you get to step up the decoction portion to get more alpha activity smaller chains of starch, then you throw it back in with the unheated portion that still have beta activity.  If you use a cool enough initial rest then your decoction will still leave the mash at a beta-friendly temp.

Lennie - this is what I was going to type. 

[bonjour]

all the enzymes wouldn't be denatured but a lot would... it would need to be a longer rest OR you could throw in another couple of hand fulls of 6 row - tons of enzymes!

These days, 6 row doesn't have much more diastatic power than 2 row.  I use 6 row for the flavor it gives, not because it's more effective at conversion.

+1

[wingnut]

I've said before that the temperature optima of the two amylases is backwards.

One way to circumvent this, is to do decoction mashing.  This way you get to step up the decoction portion to get more alpha activity smaller chains of starch, then you throw it back in with the unheated portion that still have beta activity.  If you use a cool enough initial rest then your decoction will still leave the mash at a beta-friendly temp.

I like this idea...essentially have two mashes.  One at 149 or so, and one at 158 or so and just keep moving grain back and forth. 

However the fundimental  thing that will be accomplished is wort with less body and is highly fermentable, and you could get a very similar effect by just adding sugar and water to think out the wort...a lot easier in my book! (unless you are observing the German purity law)

[nateo]

Tomsawyer - I use decoction mashes on my big Belgians where I'm going for a very fermentable wort. I'll dough in around 100 *F, pull a big decoction, bring the decoction up to 156-158 *F or so for 15min, then boil and add back to the rest of the mash to bring it up to the 140's, sometimes using additional boiling water to get it up there.

I think it's important to the think about each technique as just a tool in the toolbox. I've made an all-malt tripel using the above mash schedule, and one using just a single step at 149 + sugar, and one using the above mash + sugar, The FG's on both of the first two beers were within 0.001 of each other, but the all-malt one was noticeably thicker and not as pleasingly dry as the one I added sugar to as well. The one I had the more fermentable wort + sugar turned out the best, IMO.