Step Mash Theory - A Technical Question

[goatherder]

A few posts in this pilsner thread and a recent post in AHA techtalk got me thinking.

I'm looking for some discussion around the step-mash technique of separating out the beta-amylase and alpha-amylase rest. In a nutshell, some mashers do a beta rest at 60-63C and follow this with an alpha rest at 68-72C. The beta rest causes starches to break down into fermentable mono and di-saccharides. The alpha rest breaks these same starches down into longer chain sugars. Noonan presents this method as part of the mash schedule in his book.

There seems to be some support for the theory that well-modified malts finish conversion after 15-20 minutes. Following this logic, a beta rest at 60-63C for 20 minutes or more should give complete conversion of the starches into short chain sugars. If this is correct, what function would an alpha rest serve if there are minimal starches left to break down? Or are the enzymatic reactions more complex than this - do the alpha and the beta amylase act on different sets of source starches for example?

It seems to me, based on this thinking, that a dextrin rest following a sac rest isn't going to achieve anything because there is nothing left for the alpha enzymes to break down. If you wanted to do separate dex/sac rests, then the proper order would be do the high temp first then cool down to the low temp - limiting your time at this temp of course to avoid complete degredation of the dextrins. Or is the answer simply spending a short time in the beta range before stepping up?

I'm not keen on getting into a debate on step mash vs single infusion, I'm just after some comments on this theory. Any thoughts?

 

[Online Brewing Supplies]

A few posts in this pilsner thread and a recent post in AHA techtalk got me thinking.

I'm looking for some discussion around the step-mash technique of separating out the beta-amylase and alpha-amylase rest. In a nutshell, some mashers do a beta rest at 60-63C and follow this with an alpha rest at 68-72C. The beta rest causes starches to break down into fermentable mono and di-saccharides. The alpha rest breaks these same starches down into longer chain sugars. Noonan presents this method as part of the mash schedule in his book.

There seems to be some support for the theory that well-modified malts finish conversion after 15-20 minutes. Following this logic, a beta rest at 60-63C for 20 minutes or more should give complete conversion of the starches into short chain sugars. If this is correct, what function would an alpha rest serve if there are minimal starches left to break down? Or are the enzymatic reactions more complex than this - do the alpha and the beta amylase act on different sets of source starches for example?

It seems to me, based on this thinking, that a dextrin rest following a sac rest isn't going to achieve anything because there is nothing left for the alpha enzymes to break down. If you wanted to do separate dex/sac rests, then the proper order would be do the high temp first then cool down to the low temp - limiting your time at this temp of course to avoid complete degredation of the dextrins. Or is the answer simply spending a short time in the beta range before stepping up?

I'm not keen on getting into a debate on step mash vs single infusion, I'm just after some comments on this theory. Any thoughts?

First off your not likley to achieve conversion in 20 minutes at home.These times would represent laboratory times done in ideal situations(fine grind).So forget that.Do a iodine test to confirm negative starch result. So assuming that you dont need to do a protien rest at say 55c. you head striaght to beta rest to break down your starches the longer you spend at this temp the lower will be your (RDF) real degree of fermentation.IE lower FG.this is because you are producing more maltose/maltotriose ratio.When you head for your high rest say 70-72c you start to produce dextrins which are less fermentable.So a beer with an initial rest of higher than 67 will produce a beer which has higher levels of dextrins and there fore less fermentable and a percieved bigger body.In simple terms alpha is converting some of the work the beta has done the preparation on. Kind of hard to explain technically in words but it does make a lot of difference.
Cheers Neville
GryphonBrewing

 

[NickB]

Wow, very timely thread, as I was considering trying my first step-mash tomorrow! Would love to know some more details from the more experienced brewers on this subject.

Cheers

Nick

 

[warrenlw63]

I'm not keen on getting into a debate on step mash vs single infusion

Ahhhh but yer will goat.. yer will. :lol:

I'll refrain from firing the first shot because in principal I think you're right.

In all honesty "some" of today's malts are so attuned to auto pilot that I'm inclined to think that one temp will do the job regardless. That's even omitting the protein rest and mashout.

The problem with holding a consistent (read; uniform) temp on our inconsistent jerry-rigged equipment is near on impossible. Case in point... jam a thermometer in differing points of your mash and recoil in horror at the overall differences. Hotspots are everywhere :blink:

I'll wait for the Palmer/Noonan/Daniels/Miller/Kunzeites to elaborate.

Warren -

 

[Zwickel]

...you head striaght to beta rest to break down your starches the longer you spend at this temp the lower will be your (RDF) real degree of fermentation.IE lower FG.this is because you are producing more maltose/maltotriose ratio.When you head for your high rest say 70-72c you start to produce dextrins which are less fermentable.So a beer with an initial rest of higher than 67 will produce a beer which has higher levels of dextrins and there fore less fermentable and a percieved bigger body.In simple terms alpha is converting some of the work the beta has done the preparation on. Kind of hard to explain technically in words but it does make a lot of difference

that exactly represents my position, well said because of my poor english I cant explain well.
I just wrote a response to a PM, part of it Ill repeat here:
Englander, Australians and Americans are used to drink many sorts of ales, all of it are top fermenting and aromatic beers.
Not so in Germany, Netherland, Danmark, Czech republic, France and Italy.
There the most spreaded beers are bottom fermented lager and/or pilsener beers.
Someone who used to drink ales, perhaps would say the German Pilsener tastes flat, nonararomatic, nothing special.
Other Hand someone who used to drink european Pilseners would say, that ales are overloaded with esters and arome.
So I can understand that for Australians a beer should taste a little aromatic, not that flat and dry as we used to.
For that a single rest at around 66C is just fine, both (alpha and beta) enzymes can do their work at the same time.
For myself that would produce too much unfermentable sugar, resulting a too malty, heavy beer (for myself only).
Thats why I try to convert as much starch as I can at 63 (maltose rest) by using the beta amylase, into fermentable sugar, so there is not much starch left to get converted into unfermentable sugar by the alpha amylase.
Result is a very dry (you might say flat) nonaromatic Pilsener, the only arome one may taste, comes out of the hops.
In the above mentioned thread someone posted a recipe for a North German Pilsener and recommended a single step mash at 67C.
My Opinion about that: That will never become a North German Pilsener.
NGP is a very, very dry and bitter Pilsener, you may reach only if you leave the beta amylase working for at least one hour and do a very short rest at around 72C.
Of course, that posted recipe might be a very tasty beer, no doubts, but it will never be what its supposed be.
I dont wanna say this or that beer is better or worse, it very depends on the individual preferences, but if we wanna do an authentic clone, we have to do it the original way, otherwise it will not become a clone.

Fortunately we homebrewers have the freedom to do our beer as we like to do, without boundaries.

Cheers :beer:

 

[Darren]

Only thing I have to add is that you cannot go back in temp.

Once you get into alpha amylase temps (67+) most the beta amylase will be killed (denatured).

I agree 67 is too high for a pils. Usually mash mine at 63.

cheers

Darren

 

[Screwtop]

that exactly represents my position, well said because of my poor english I cant explain well.
I just wrote a response to a PM, part of it Ill repeat here:
Englander, Australians and Americans are used to drink many sorts of ales, all of it are top fermenting and aromatic beers.
Not so in Germany, Netherland, Danmark, Czech republic, France and Italy.
There the most spreaded beers are bottom fermented lager and/or pilsener beers.
Someone who used to drink ales, perhaps would say the German Pilsener tastes flat, nonararomatic, nothing special.
Other Hand someone who used to drink european Pilseners would say, that ales are overloaded with esters and arome.
So I can understand that for Australians a beer should taste a little aromatic, not that flat and dry as we used to.
For that a single rest at around 66C is just fine, both (alpha and beta) enzymes can do their work at the same time.
For myself that would produce too much unfermentable sugar, resulting a too malty, heavy beer (for myself only).
Thats why I try to convert as much starch as I can at 63 (maltose rest) by using the beta amylase, into fermentable sugar, so there is not much starch left to get converted into unfermentable sugar by the alpha amylase.
Result is a very dry (you might say flat) nonaromatic Pilsener, the only arome one may taste, comes out of the hops.
In the above mentioned thread someone posted a recipe for a North German Pilsener and recommended a single step mash at 67C.
My Opinion about that: That will never become a North German Pilsener.
NGP is a very, very dry and bitter Pilsener, you may reach only if you leave the beta amylase working for at least one hour and do a very short rest at around 72C.
Of course, that posted recipe might be a very tasty beer, no doubts, but it will never be what its supposed be.
I dont wanna say this or that beer is better or worse, it very depends on the individual preferences, but if we wanna do an authentic clone, we have to do it the original way, otherwise it will not become a clone.

Fortunately we homebrewers have the freedom to do our beer as we like to do, without boundaries.

Cheers :beer:

Zwickel
Mashout machen auch Sie

 

[SpillsMostOfIt]

The problem with holding a consistent (read; uniform) temp on our inconsistent jerry-rigged equipment is near on impossible. Case in point... jam a thermometer in differing points of your mash and recoil in horror at the overall differences. Hotspots are everywhere :blink:

I take exception at this statement. My equipment is *consistently* jerry-rigged.

Even with my full-volume mashing 'technique', the temperature variation can be a degree or more across the vessel. I get in there with my thermometer and potato masher every so often to agitate it and watch what's happening. It appears to be much more complex than a simple curve from inside to outside. So, I guess that there are all sorts of things happening in there rather than a simple 'all beta, no alpha' situation. I couldn't even say (even if I knew what I was talking about) that I was likely to get X% alpha and Y% beta action.

It's a bit too complicated for me. I think the best solution is to stop measuring.

 

[matti]

The alpha amylase temperature of +65 is of my understanding briefer or non existent in light pilsners and longer in heavy Pilsners.

According to Noonan the rests temp has to be precise in temperature and time to be able to produce the style of pilsner or lager you are seeking.

He also mentions that one can not yield a fully dextrinous wort wthout it.

I guess that is arguable with well modified malts, though you will get a fuller darker pilsner with a saccharification rest proving the sparging is satisfactory.

 

[Malnourished]

There seems to be some support for the theory that well-modified malts finish conversion after 15-20 minutes. Following this logic, a beta rest at 60-63C for 20 minutes or more should give complete conversion of the starches into short chain sugars. If this is correct, what function would an alpha rest serve if there are minimal starches left to break down? Or are the enzymatic reactions more complex than this - do the alpha and the beta amylase act on different sets of source starches for example?

Yeah, it's the old nibbler (beta) and chomper (alpha) analogy. The beta amylases 'nibble' on the end of the starches, whereas the alpha amylases 'chomp' them down the middle. If this is accurate it makes sense to me that beta amylase would work far slower than alpha amylase, and it's presumably why higher temperatures lead to faster conversion. I doubt you'd get close to conversion in 20 minutes at 60C.

Sorry to get so technical. :lol:

 

[Screwtop]

Is anyone direct heating their mash tun, can't use my immersion heater to raise from protien rest because it burns the sticky mash. Is there a problem direct heating a SS mash tun, I want to try a small gas burner for stepping instead. Have a spare HLT but no pump for recirc yet.

 

[oldbugman]

Is anyone direct heating their mash tun, can't use my immersion heater to raise from protien rest because it burns the sticky mash. Is there a problem direct heating a SS mash tun, I want to try a small gas burner for stepping instead. Have a spare HLT but no pump for recirc yet.

Cant use the imersion and keep it moving through the mash?(not just plonking it in)

 

[AndrewQLD]

Is anyone direct heating their mash tun, can't use my immersion heater to raise from protien rest because it burns the sticky mash. Is there a problem direct heating a SS mash tun, I want to try a small gas burner for stepping instead. Have a spare HLT but no pump for recirc yet.

Screwtop,
I direct fired my S/S mash tun using a small double gas ring until I got my immersion heater and then I blew the immersion heater 3rd time I used it. To be honest I found the gas ring much easier to use, just a quick stir with a spoon every now and then, a lot easier than juggling immersion heater and spoon, and the temp ramps up a lot quicker.

Cheers
Andrew

 

[Ross]

Yep,

Immersion heaters don't last 5 minutes if you don't keep them moving, as I found out to my cost . Since replacement though I have no trouble raising mash temp with it (just over 1c a minute typically), just got to keep it moving. Unfortunately I have no faucility to direct fire the mash tun but I reckon it should work fine if you keep it stirred.

cheers Ross

 

[SpillsMostOfIt]

I use my immersion heater to help with mash temperature in my FB Boiler (BIAB) and the only issue was that if you use it as a mixer too violently you can pull the power cord out of its strain relief (some heat shrink fixed that).

I did a half-sized batch in my small setup on the (gas) stove top recently and with the burner on as low as it would go, the mash temp stayed just right. I reckon I was lucky though and wouldn't count on it happening ever again.

 

[Darren]

I have burned a mash with bottom heat. Low heat and stirring is the go and NEVER walk away from it.

cheers

Darren

 

[bugwan]

I was a contributor to the Pilsener thread that Goatherder was referring to in his OP, getting a bit off topic with immersion heater queries... I only tried this last week for the first time (I usually bring up temps with infusions).

I have to say, the immersion heater (always moving) is a superb way to look after temps accurately. No chance of under/over shooting the target (assuming you're carefully watching temps) or running out of room in your esky.

I'll be mashing in my next multi-step mash at a 3:1 ratio and stepping up with the immersion heater. The taste test will tell all I guess, but the convenience of it appeals to me...

 

[Darren]

I was a contributor to the Pilsener thread that Goatherder was referring to in his OP, getting a bit off topic with immersion heater queries... I only tried this last week for the first time (I usually bring up temps with infusions).

I have to say, the immersion heater (always moving) is a superb way to look after temps accurately. No chance of under/over shooting the target (assuming you're carefully watching temps) or running out of room in your esky.

the convenience of it appeals to me...

Bugwan,

How quickly can you raise the temps? Actually, what are your temps?

Myself, I can't see anything more convenient than allowing the maltster to define your single-infusion-mash schedule for you. Pilsner style mash low (61-64), ale style, mash a bit higher (65-72)

Nothing worse to your ales than think you ned a protein rest

cheers

Darren

 

[Screwtop]

Been using mine for about 10 months, always stir and heat at the same time, works well for step mashing and stepping to mash out, BUT! Four times it has burnt the mash even while stirring and ended up with mash burnt on so hard it has taken all sorts of measures to clean the carbon off. Usually it's when the ratio of grist to water is less than 2:1 and on 3 of the 4 occasions it has been when raising from a protien rest when the mash is very starchy.

Threw out a batch today after another burn't mash, can't stand the taste of murnt mash. Thanks for the advice Andrew, converted the mash tun today, removed the insulation from the bottom and snapped the inner lugs off the 3 ring burner so the tun would sit properly on the outer lugs. Used the small inner burner and second burner which heated the mash beautifully.

 

[MHB]

This is a method I have been playing around with, it's a way to step mash by making additions of hot (near boiling) water.

It does require some preplanning, but in essence it's very similar to the stepping process involved with decoction mashing.

The advantages of hot water additions are that you get very sharp transitions from one temperature step to the next, and that there is no extra equipment required.

Just as a rough example:-
Say you expect to get around 5.5 L of sweet water from each 1 Kg of grain, your total water requirements are going to be around 6.5 L/Kg (1L staying in the grain).

Say you mash in heavy ~3:1 - thats 3 L of the 6.5.
You require ~1.5 L/Kg to sparge - thats a total of 4.5 L/Kg
Leaving ~ 2 L/kg to make hot water additions with

Assuming that the hot water additions are at around 95C, using the standard decoction equations*.
The 2 L has enough heating power at 95C to raise a mash about 20 C, or from 60 to 80 C, and to do this very quickly.
Or with smaller additions; to make several other rests between 60 and 80C

Obviously just dumping 2 L of boiling water into the mash tun wouldnt be a good idea (yes Darren it would kill a lot of enzymes ). Ideally the hot water would be introducer over several minutes - with constant stirring of the mash to keep the temperature homogeneous.

Mechanically underletting from the HLT, through a well secured false bottom would be ideal (just keep stirring).

There are many options and variables, if you mashed in at 2.5:1, cut your sparge water back a bit and got you addition up to 98 C.
Had you mashed in at 50 C, you would have enough heating power to get 78 C (just).

Everyone's system is going to respond differently and depending on all the variables including:-
Your choices of malt
The type of beer you are making (heavy mashers are better for darker beers)
How good your insulation is
How good you are at stirring
This method will be of varying amounts of usefulness - but worth having a play with.

MHB

*For the pedants
I am aware that there is a difference between the thermal mass of water and a mash, but I can't put my hand on the full equations for hot water additions easily, but as I have the decoction** one memorised I used that one and the back of an envelope (literally); from recollection it made a 2-3 C difference in a similar case.

**Boil Volume =[(Desired Change in Temperature) X (Volume Mash + Addition)] / [(Temperature of addition (i.e.95)) - (Temperature of the Mash)]

M