Why mash out?

[azazel1024]

With several tests, if I mash out with BiaB at 170F I regularly get 3 points better efficiency than if I mash out at 150F. I also tend to be able to squeeze a little more wort out of the grain bag to. Though really, we are probably talking like getting half a pint extra out of 10lbs of grain. Since it's all in the pot anyway, I heat it up to 170F, stir a few times and then yank the grain bag out and let it drain.

 

[Gavin C]

I've read this elsewhere, how does this work? I could see if you brought it up to a boil you may release some of the "trapped" sugars between the packed grain bed through agitation of the boil thus averaging out the sugar concentration. But we're not boiling.

Still learning and want to understand, not questioning your experience.

No worries mate. Question away. I am certainly no oracle of wisdom on the subject. I'm just regurgitating the purported functions of a mash-out I have read elsewhere and put into practice in my rudimentary setup.

It's of greater importance I believe in flysparging as others have alluded to, where the brewer desires to denature the amylase enzymatic activity at a set time while slowly rinsing the grains of their sugars as the hot sparge water pushes the denser, cooler, sugar-laden sweet-wort out of the mash-tun and into the kettle where it can be heated, further denaturing ezymes that may as yet be still active in the runnings.

I don't utilize a three vessel setup so my understanding is based solely in the theory and not the pratical aspects of performing a fly-sparge I'm afraid. I am a novice and am here to learn.

 

[motobrewer]

the solubility of sucrose in water is 259 grams / 100 g water at 50C.

at 70C, it's 323 g/100g.

or, 25% more.

 

[Gavin C]

the solubility of sucrose in water is 259 grams / 100 g water at 50C.

at 70C, it's 323 g/100g.

or, 25% more.

Thanks motobrewer. I reckon that's the answer to the OP's question and to much of our ponderings. Thanks for the education.

 

[doug293cz]

the solubility of sucrose in water is 259 grams / 100 g water at 50C.

at 70C, it's 323 g/100g.

or, 25% more.

If you had sugar in excess of the solubility limit at mash temps, then that would matter. But the fact is, you don't come even close to the solubility limit. And wort is primarily maltose, which is important because maltose has lower solubility than sucrose (which is the most soluble of all sugars.)

So, let's look at maltose. From here, the solubility of maltose in water at 66.3°C (151.3°F) is 200g/100g or 66.7%. Which works out to an SG of somewhere around 1.300 (depending on how good the Brix to SG calculators are at concentrations that high.) Most worts have less than 1/3 of the solubility limit, and even huge beers are less than 1/2 of the limit. You don't need higher temps to dissolve all the sugar into the wort.

Brew on

 

[doug293cz]

Thanks motobrewer. I reckon that's the answer to the OP's question and to much of our ponderings. Thanks for the education.

No, it's not. See my post above this one.

Brew on

 

[azazel1024]

Solubility rate is often influenced by solubility limit though. So all of the maltose might dissolve in to the wort faster at 170F than at 150F...

Just saying. Not that I am aware that it actually makes a difference, but I DO get a couple points more efficiency is I mash out at 170F faster mashing rather than at 150F.

 

[doug293cz]

Solubility rate is often influenced by solubility limit though. So all of the maltose might dissolve in to the wort faster at 170F than at 150F...

Just saying. Not that I am aware that it actually makes a difference, but I DO get a couple points more efficiency is I mash out at 170F faster mashing rather than at 150F.

Let's look a what's going on in a mash dynamically (https://www.homebrewtalk.com/wiki/index.php/The_Theory_of_Mashing)

• First, water has to diffuse into the grain particles in order to gelatinize and then solubilize the starches.
• Then, the soluble starch has to diffuse out of the grain into the wort
• Once the starch is in the wort, the amylase enzymes can convert it to sugars (according to what I've read, the vast majority of the enzymatic action takes place in the wort.)

So, the sugar is already in solution when it is formed. You never have solid sugar that needs to be dissolved.

Why then does your efficiency go up when you mash out? Most likely because the solubilization of the starch is not complete at the end of your mash. A test that is often suggested is to run an iodine conversion test on just the wort, and then mostly grain with a little wort. Often the wort alone tests negative (no starch), while the grain still tests positive for starch. Remember, we are dependent on diffusion for things to happen. Grain particles are very dense, so diffusion into them is very slow. Diffusion into gelatinized starch is faster, and diffusion in the wort is faster still. In practice what happens is the surface layer of a grain particle is gelatinized and solubilized before any water gets into the core of the particle. So, the surface starch is dissolved into the wort first, and then another layer, and so on, until the starch in the core is finally solubilized. Starch conversion cannot finish until the core has been solubilized.

With a normal grain crush, a 60 minute mash may not be long enough to complete conversion of the cores of the particles. When you mash out, diffusion speeds up, as does the reaction rate of the amylase enzyme, and also the denaturing rate of the enzyme. So, you are getting a little more starch conversion during the mash out, at least until the amylase is completely denatured. With a longer mash, or finer crush, the efficiency gain from a mash out will decrease or even disappear.

Brew on

 

[jtp137]

I never do a mash out even when i fly sparge for two reasons

1. I think you would have to do a mash out for more than 15 minutes to denature the enzymes

2. If I mash at 152 and dont do a mash out and the wort becomes more fermentable during the long fly sparge. i will mash at 154 next time

 

[Yooper]

If you had sugar in excess of the solubility limit at mash temps, then that would matter. But the fact is, you don't come even close to the solubility limit. And wort is primarily maltose, which is important because maltose has lower solubility than sucrose (which is the most soluble of all sugars.)

So, let's look at maltose. From here, the solubility of maltose in water at 66.3°C (151.3°F) is 200g/100g or 66.7%. Which works out to an SG of somewhere around 1.300 (depending on how good the Brix to SG calculators are at concentrations that high.) Most worts have less than 1/3 of the solubility limit, and even huge beers are less than 1/2 of the limit. You don't need higher temps to dissolve all the sugar into the wort.

Brew on

Correct. Kai Troester has publish his data indicating that cold water sparging works as well as hot water sparging, at least from an efficiency standpoint. It was at a National Homebrew Conference a while back, and I don't remember all of the details, but I remember that point quite clearly.

 

[Gavin C]

Looks like I'm none the wiser then after all. Thanks Doug, mottobrewer and Yooper.

 

[Yooper]

Looks like I'm none the wiser then after all. Thanks Doug, mottobrewer and Yooper.

No, not at all! Intuitively, I'd say that you're on to something.

But Kai's data showed that diffusion is the mechanism at play, and it is not temperature dependent.

I thought, just like with making sugar syrups, that sugars dissolved better in hot liquid, but Kai explained that the sugars are already dissolved and that diffusion is the principle behind it.

 

[Gavin C]

No, not at all! Intuitively, I'd say that you're on to something.

But Kai's data showed that diffusion is the mechanism at play, and it is not temperature dependent.

I thought, just like with making sugar syrups, that sugars dissolved better in hot liquid, but Kai explained that the sugars are already dissolved and that diffusion is the principle behind it.

So would it be analogous to brownian motion in gasses only with fluids? The sugars in fluid x will more readily diffuse into fluid y if Brownian motion (not sure if that is applicable to fluids but I don't know the correct term) is more rapid in the fluids. That is to say, the more heat in the system the more rapid the diffusion of the differing fluids into each other. Rather than increased dilution it is increased fluid miscibility. The fluids being the sweet-wort and the Sparge water.

Perhaps my interpretation is off the mark.

 

[doug293cz]

So would it be analogous to brownian motion in gasses only with fluids? The sugars in fluid x will more readily diffuse into fluid y if Brownian motion (not sure if that is applicable to fluids but I don't know the correct term) is more rapid in the fluids. That is to say, the more heat in the system the more rapid the diffusion of the differing fluids into each other. Rather than increased dilution it is increased fluid miscibility. The fluids being the sweet-wort and the Sparge water.

Perhaps my interpretation is off the mark.

Brownian motion is caused by the same molecular vibrations that cause diffusion. The vibrations of molecules in gases and liquids are random, so over short periods of time you can get more molecules going in one direction than the other within a small volume. This imbalance of motion can push a small particle in the direction that more of the smaller molecules are going.

Diffusion is also due to the random vibrations of molecules, but happens when you have a concentration gradient. Let's do a thought experiment. Imagine an infinitely thin permeable membrane with a higher concentration of molecule "A" on one side than the other. The molecules of "A" bouncing around occasionally bump into the membrane, and molecules that hit the membrane pass thru it. Since there are more "A" molecules on one side of the membrane than the other, there will be more collisions with the membrane on the high concentration side than the low concentration side. This means more molecules pass from the high concentration side to the low concentration side than from low to high. So, there is a net flow of "A" molecules from the high concentration side to the low concentration side. If you take away the membrane, nothing changes. More molecules of "A" cross the infinitely thin volume of space (a mathematical "surface") from the higher concentration side of the surface to the lower concentration side, because more come at it from the higher concentration side. This is diffusion. The higher the local concentration difference from one point to another (the gradient) the faster the diffusion.

The rate of diffusion is affected by two other things: the mobility of molecule "A" in the surrounding medium, and the speed at which the molecules of "A" are moving. Temperature is a measure of how fast molecules are moving; higher temps equal faster motion, and faster motion means faster diffusion. Molecular mobility is affected by volume density of the medium (volume of molecules/volume of space), and the structural rigidity of the medium. Higher volume density means less open space between molecules of the medium thru which the diffusing molecules can move, resulting in lower mobility. Lower rigidity means it's easier for a diffusing molecule to push molecules of the medium out of the way so it can get by them. Solids are rigid structurally, and usually have high volume density, so mobility within solids is extremely low. Increasing temperature causes solids and liquids to expand thus reducing their volume density somewhat, and increasing mobility. Increasing tempeature also reduces the rigidity of solids slightly, which also increase mobility. Liquids also have high volume density, but no structural rigidity, so mobility in liquids is significantly higher than in solids. Gases have low volume density, and no structural rigidity, so mobility is highest in gases. To summarize:

• Higher concentration gradient drives faster diffusion
• Higher temperature drives faster diffusion
• Higher mobility allows faster diffusion

And, diffusion in gases is much faster than diffusion in liquids which is much faster than diffusion in solids.

Does this help? If you need something clarified, just ask (but you see what happens when you get me started. )

Brew on

 

[OkanaganMike]

Why do I feel like I just walked into Sheldon Cooper's apartment?
.....and thats what they call the Big Bang. ..... BANG!

 

[doug293cz]

Why do I feel like I just walked into Sheldon Cooper's apartment?
.....and thats what they call the Big Bang. ..... BANG!

Hopefully, I'm not as socially unaware, and I'm definitely not a virgin

Brew on

 

[aprichman]

the solubility of sucrose in water is 259 grams / 100 g water at 50C.

at 70C, it's 323 g/100g.

or, 25% more.

This was my line of thought as well - organic compounds are more soluble at higher temperatures. Raising the temperature when mashing out should increase efficiency.

 

[skw]

Correct. Kai Troester has publish his data indicating that cold water sparging works as well as hot water sparging, at least from an efficiency standpoint. It was at a National Homebrew Conference a while back, and I don't remember all of the details, but I remember that point quite clearly.

I've stopped heating my sparge water since, and I'm not mashing out either.
Brew house efficiency did not change, my time efficiency however has improved.

 

[doug293cz]

the solubility of sucrose in water is 259 grams / 100 g water at 50C.

at 70C, it's 323 g/100g.

or, 25% more.

This was my line of thought as well - organic compounds are more soluble at higher temperatures. Raising the temperature when mashing out should increase efficiency.

Assuming that higher solubility at higher temperatures is an important effect with respect to mashing is an extremely common misconception. If you had read and understood my earlier response to the quoted post by @motobrewer (https://www.homebrewtalk.com/showpost.php?p=6829662&postcount=35.), you would realize that the higher solubility doesn't matter. The sugar is created already dissolved in the wort. There is no undissolved sugar to dissolve (although there may be unconverted starch in the grain particles.)

If you want to understand more, read my other posts in this thread following post #35. They're fairly technical (and one is long, and quite a slog), but if you understand them, you will have a better understanding of the microscopic physical processes that control mashing. If you disagree with what I have written, tell me why, and we can discuss it. If you don't care, that's fine too, but then you shouldn't be responding on the topic.

Brew on

 

[aprichman]

Assuming that higher solubility at higher temperatures is an important effect with respect to mashing is an extremely common misconception. If you had read and understood my earlier response to the quoted post by @motobrewer (https://www.homebrewtalk.com/showpost.php?p=6829662&postcount=35.), you would realize that the higher solubility doesn't matter. The sugar is created already dissolved in the wort. There is no undissolved sugar to dissolve (although there may be unconverted starch in the grain particles.)

If you want to understand more, read my other posts in this thread following post #35. They're fairly technical (and one is long, and quite a slog), but if you understand them, you will have a better understanding of the microscopic physical processes that control mashing. If you disagree with what I have written, tell me why, and we can discuss it. If you don't care, that's fine too, but then you shouldn't be responding on the topic.

Brew on

There are other organic compounds that make up beer that may be more readily dissolved at a higher temperature and could play a role in sensory perception. I'd be interested to see a study that examined sparge temperatures in relation to the perception of beer.

 

[doug293cz]

There are other organic compounds that make up beer that may be more readily dissolved at a higher temperature and could play a role in sensory perception. I'd be interested to see a study that examined sparge temperatures in relation to the perception of beer.

The one data point I am aware of (http://braukaiser.com/blog/blog/2009/05/12/cold-water-sparging/) concluded sparge temp didn't make a significant difference in the perception of the beer. It was however an imperfect experiment due to very minor recipe changes between the hot and cold sparge batches. My guess is that a series of well controlled experiments would show that there are many more important factors than sparge temp that affect the beer perception, even if you could eventually show some detectable difference due to sparge temp. I'm not going to run those experiments. 1: because I don't think it's worthwhile, and 2: because I can't control all the other variables well enough to be able to separate out a minor effect due to sparge temp. But, if someone does do such experiments, I will review the results. And, if the results are convincing, I will change my opinions.

Brew on

 

[beerme70]

I brewed a Biere de Garde last weekend. My setup wouldn't allow me to do my usual single infusion mash with mash out (ala BeerSmith2) because of the lack of volume of my MLT (needed 16 gallons, and the MLT is a shade under 15), so I went with the single infusion, no mash out, and batch sparge. Brewhouse efficiency is around 72% on average for the home brewer, and my measured efficiency was 74.4%, about 1.5% HIGHER than usual. I may never do a mash out again.

 

[joshesmusica]

Beersmith only tells you to do a mashout if you've chosen a mash profile that includes a mashout. Go back in to your mash profile and select essentially the same mash except that it says "no mashout" and beersmith will stop telling you to do a mashout.

This is what I was going to say, that you should be telling Beersmith what to do not the other way around. If you don't find a default profile that fits your actual process then modify one and save it. You can add and delete steps from within the mash profile page.

i understand that I can change beersmith to whatever way i want it to be set up. that wasn't my question. my question was why does the stock profile for BIAB in beersmith automatically tell you to do a mash out in all four BIAB profiles (light, medium, full body, and pilsner step mashes)?

 

[azazel1024]

Let's look a what's going on in a mash dynamically (https://www.homebrewtalk.com/wiki/index.php/The_Theory_of_Mashing)

• First, water has to diffuse into the grain particles in order to gelatinize and then solubilize the starches.
• Then, the soluble starch has to diffuse out of the grain into the wort
• Once the starch is in the wort, the amylase enzymes can convert it to sugars (according to what I've read, the vast majority of the enzymatic action takes place in the wort.)

So, the sugar is already in solution when it is formed. You never have solid sugar that needs to be dissolved.

Why then does your efficiency go up when you mash out? Most likely because the solubilization of the starch is not complete at the end of your mash. A test that is often suggested is to run an iodine conversion test on just the wort, and then mostly grain with a little wort. Often the wort alone tests negative (no starch), while the grain still tests positive for starch. Remember, we are dependent on diffusion for things to happen. Grain particles are very dense, so diffusion into them is very slow. Diffusion into gelatinized starch is faster, and diffusion in the wort is faster still. In practice what happens is the surface layer of a grain particle is gelatinized and solubilized before any water gets into the core of the particle. So, the surface starch is dissolved into the wort first, and then another layer, and so on, until the starch in the core is finally solubilized. Starch conversion cannot finish until the core has been solubilized.

With a normal grain crush, a 60 minute mash may not be long enough to complete conversion of the cores of the particles. When you mash out, diffusion speeds up, as does the reaction rate of the amylase enzyme, and also the denaturing rate of the enzyme. So, you are getting a little more starch conversion during the mash out, at least until the amylase is completely denatured. With a longer mash, or finer crush, the efficiency gain from a mash out will decrease or even disappear.

Brew on

Maybe. I dunno. When I've done iodine tests, I've never had one show starch present after about 25-30 minutes, but I always do a 60 minute mash anyway. Only time I did have starch later on is when I mashed cranberries and probably dropped the PH too low for the enzyemes, causing them to denature before finishing conversion.

 

[Yooper]

This was my line of thought as well - organic compounds are more soluble at higher temperatures. Raising the temperature when mashing out should increase efficiency.

But in a mash that is already converted, it doesn't. There aren't more sugars to dissolve.

i understand that I can change beersmith to whatever way i want it to be set up. that wasn't my question. my question was why does the stock profile for BIAB in beersmith automatically tell you to do a mash out in all four BIAB profiles (light, medium, full body, and pilsner step mashes)?

I think it's because many brewers mash out simply out of tradition. Even I usually mash out- partly because I've always done it and my HERMS makes it simple, partly because it ensures complete conversion if it didn't happen during the mash since I raise the temperature over 15 minutes, and partly because then my wort is already closer to boiling when it hits the boil kettle- it's 168 degrees so it's about 16 degrees higher than the mash was.

If I don't mash out, say, because I decided to batch sparge and my sparge water is only 150 degrees but my mash is over and I don't want to wait- I go ahead and do it.

Remember that BIAB and things like no-sparge brewing are really very new in brewing.

Maybe. I dunno. When I've done iodine tests, I've never had one show starch present after about 25-30 minutes, but I always do a 60 minute mash anyway. Only time I did have starch later on is when I mashed cranberries and probably dropped the PH too low for the enzyemes, causing them to denature before finishing conversion.

The mash is almost always going to be converted by 20-30 minutes, unless you're doing a cool (say, 147 degree) mash or using lots of adjuncts like oats or corn. I still mash for 60 minutes, because complete conversion doesn't necessarily mean the mash is "done", though. There are still long chain sugars being worked on, making short chain sugars.

 

[Gavin C]

@doug293cz

Very informative post #44 Doug with regard to Brownian motion, diffusion etc. Just one question. Does your prose indicate a support or a rebuttal of the "greater miscibility hypothesis" at the higher temps that I was trying to describe, (probably very poorly).

Easy now. Simple answer please. It's still early in my neck of the woods.

Only kidding. Type away. Verbose erudition is not to be feared. There is a time and a place for it and it is here.

 

[chickypad]

i understand that I can change beersmith to whatever way i want it to be set up. that wasn't my question. my question was why does the stock profile for BIAB in beersmith automatically tell you to do a mash out in all four BIAB profiles (light, medium, full body, and pilsner step mashes)?

Who knows, there's just not many default options period with BIAB - for example nothing but full volume mash. Many of us do a sparge because we're short on pot space. I think he probably just picked what he thought was the most common to include. Maybe there will be more default choices if there is ever another version given the increased popularity of BIAB.

 

[masonsjax]

Does Kool Aid need to be heated up before it can be poured quickly into a glass?

 

[OkanaganMike]

Whats the OG?

 

[Gavin C]

Whats the OG?

Original Gravity of the finished wort prior to pitching yeast.