Grain crush feedback

[guillaume]

I'm brewing in the afternoon and I thought I could get some input on my crush while I'm at it.

I sprayed water on the grains and let them rest for a bit before crushing with my Cereal Killer at around 0.29. All grains seems to be crushed, but alot are still inside the husk.

 

[lhommedieu]

This is what Noonan depicts as well-crushed grain in Brewing Lager Beers:

There was a post made recently on HBT that described how to evaluate crush according to the percentage of crush held on sieves. I purchased a set of standard sieves via eBay for about $100 and am going to crush some leftover grain today to see what results I get. If you're interested, I'll post my results.

The gist of the post is below; I compared it to Noonan's and they are pretty much the same. The ounce units are figured as a percentage of a pound of grain.

On #14 Screen: husks held; 15% of grain by weight; 2.4 oz/lb.
On #30 Screen: coarse grits held; 25% of grain by weight; 4 oz/lb.
On #60 Screen: fine grits held; 30 % of grain by weight; 4.8 oz/lb.
On bottom tray: flour; 30% of grain by weight; 4.8 oz/lb.

According to Noonan in Brewing Lager Beer:

On #10 Screen: husks held; 5% of grain by weight
On #14 Screen: husks held; 5% of grain by weight
On #18 Screen: husks held; 5% of grain by weight

Note: Above percentages based on 15% for all three screens.

On #30 Screen: coarse grits held; 25% of grain by weight
On #60 Screen: fine grits held; 30 % of grain by weight
On #100 Screen: flour held; 20% of grain by weight
On bottom tray: fine flour; 10% of grain by weight

Noonan’s method uses three more screens (#10, #18, #100) but mass distribution is essentially the same.

 

[guillaume]

This is what Noonan depicts as well-crushed grain in Brewing Lager Beers:

There was a post made recently on HBT that described how to evaluate crush according to the percentage of crush held on sieves. I purchased a set of standard sieves via eBay for about $100 and am going to crush some leftover grain today to see what results I get. If you're interested, I'll post my results.

That would be great, with pictures as well! I'm trying to get better efficiency (to keep the same grain bill but get more wort). The next step would be to heat my sparge water. I'm using hot water directly from the sink since I'm missing a kettle to heat it up.

 

[lhommedieu]

That would be great, with pictures as well! I'm trying to get better efficiency (to keep the same grain bill but get more wort). The next step would be to heat my sparge water. I'm using hot water directly from the sink since I'm missing a kettle to heat it up.

I didn't get around to it last weekend (too many "honey do's") but I'll find the time this weekend and post my results.

 

[RM-MN]

In general the tighter you set the mill, the higher your efficiency will be but with that finer crush comes the chance for a stuck sparge as your conventional mash tun needs intact husks to form a filter when draining. You've taken the first step toward maintaining the intact husks by wetting the grain before milling as that toughens the husks so they don't tear as easily. I'd personally set the mill tighter or double mill the grain to see if I could get by without a stuck sparge but I might recommend having a paint strainer bag or a bag made of "Swiss voile" (curtain material) to dump the mash through just in case you got a badly stuck sparge as that will become the filter. You could just mash in the bag and save all the worry about a stuck sparge too. Some of us avoid the mash tun altogether and do the mash in the bag right in our boiling kettle too.

 

[doug293cz]

That would be great, with pictures as well! I'm trying to get better efficiency (to keep the same grain bill but get more wort). The next step would be to heat my sparge water. I'm using hot water directly from the sink since I'm missing a kettle to heat it up.

Hot water vs. cold water for sparge has negligible affect on efficiency, assuming you have good conversion efficiency prior to sparging. Kai did a nice experiment here to demonstrate that. If you are looking for tips on how to diagnose efficiency problems, check my post here.

Brew on

 

[lhommedieu]

I was able to crush some grain today and will post the results below. I learned a few things by going through the process:

1. 100 g of grain is sufficient to get good results. When I tried to sift 1 lb. of crushed grain through the sieves there was not a lot of movement of grain and I could not get enough flour to pass through to the other levels.

2. I needed to tighten the rollers on my Malt Mill to get a finer crush that begins to approach Noonan's numbers. This probably explains why it has been so difficult for me to get conversion using the decoction method that I have been learning: the crush has not been fine enough.

Following are pictures with commentary:

Initial crush after adjusting grain mill. I believe that the husks look fairly intact. Most of the starch still inside the husks came out during the process of agitating the sieves; I think that the decoction method, which involves both stirring and boiling the mash, will force the starch out of the husks as well.

On #14 Screen: husks held; 35% of grain by weight. My target was 15%. You can see that there is a fair amount of coarser grits mixed in with the husks, which probably accounts for the higher percentage.

On #30 Screen: coarse grits held; 31% of grain by weight. My target was 25%.

On #60 Screen: fine grits held; 13 % of grain by weight. My target was 30%.

On bottom tray: flour; 22% of grain by weight. My target was 30%.

These results are not perfect, but they begin to approach Noonan's numbers for crush percentages for lagers. I will attempt to tighten my grain mill for a finer crush and/or send the grain through twice to bring the numbers closer together, and will post the results.

 

[lhommedieu]

Just a follow-up:

I tightened the mill up as follows:

Far left side of mill between rollers: 0.35"
Middle of mill between rollers: 0.25"
Far right side of mill between rollers: 0.18"

Grain crush was approximately the same. I did notice some coarsely crushed grain mixed in with the husks, as before.

For now I'm not going to worry about the percentages. I think that I've achieved what I can do with the technology available, and it's a huge improvement on my last crush/brew. I have a feeling that the larger percentage of husks will help me during fly sparging. There is also the possibility that a greater mass of grain in the hopper will lead to a different range of percenages vs. 100 g.

The trick will be to find out if the percentages that I've achieved will lead to a stuck sparge (I don't think so) and whether a finer crush will lead to easier conversion and better efficiency (to be hoped for).

Following are some additional pictures, with captions:

Grain Mill

Sieves with bottom and lid

Crushed grain

Top sieve. A coarser top sieve (#10?) would probably result in a lesser percentage of husks.

 

[doug293cz]

What's the reasoning behind setting the mill gap to vary along the roller length? I've never seen that suggested before.

Brew on

 

[passedpawn]

What's the reasoning behind setting the mill gap to vary along the roller length? I've never seen that suggested before.

Brew on

JSP MaltMill adjusts on one side only. So, it was not intentional, but graduated by design.

 

[passedpawn]

FWIW, I have the same mill (JSP) and I have always milled as thinly as possible. I've adjusted the rest of my system so I don't get stuck sparges when lautering. It's the path to the best efficiency.

 

[lhommedieu]

What's the reasoning behind setting the mill gap to vary along the roller length? I've never seen that suggested before.

Brew on

As noted above, this particular malt mill adjusts on one side and is fixed on the other side. This results in a graduated mill gap, which means that the crush varies depending on where the grain falls between the rollers.

Edit: Although I am happy with the crush that I have now, the next chance that I get, I'll see what the crush looks like when the mill gap is even from the left side to the right side. I'm predicting that I'll have less crushed husks, more starch inside the husks, etc. I still believe that I'm going to have an easier time converting, and greater efficiency, with a finer crush.

 

[guillaume]

Hot water vs. cold water for sparge has negligible affect on efficiency, assuming you have good conversion efficiency prior to sparging. Kai did a nice experiment here to demonstrate that. If you are looking for tips on how to diagnose efficiency problems, check my post here.

Brew on

I read about kai experiments on sparge temp when I started, but I must have forgot about it.

I'll try to use a smaller gap next time and see the difference since I got about 68% efficiency on both brews I did. I got a false bottom and with this grain crush I can just drain at full speed.

 

[lhommedieu]

I read about kai experiments on sparge temp when I started, but I must have forgot about it.

I'll try to use a smaller gap next time and see the difference since I got about 68% efficiency on both brews I did. I got a false bottom and with this grain crush I can just drain at full speed.

There are good reasons to use hot water while fly sparging, particularly with a fly sparge that can take over a hour to complete. Different brewers may use different methods, but if I used cold water to fly sparge after using a decoction method, I would probably create a stuck sparge.

 

[doug293cz]

There are good reasons to use hot water while fly sparging, particularly with a fly sparge that can take over a hour to complete. Different brewers may use different methods, but if I used cold water to fly sparge after using a decoction method, I would probably create a stuck sparge.

Yes, the kinetics of getting the sugar mixed with the sparge water are different for fly sparging vs. batch sparging. In batch sparging you can stir aggressively to get the sparge water equilibrated with the wort retained in the mash. In this case you are depending on fluid shear to do the mixing.

In a properly conducted fly sparge, fluid flow thru the grain bed is very slow, so there is little shear to accelerate mixing. In this case you are almost completely dependent on diffusion, driven by sugar concentration differences, to mix the wort with water, and draw the sugar out of the grain. Since diffusion happens faster at higher temperatures, it would take significantly longer to get equivalent lauter efficiency with a cold water fly sparge.

Not sure I believe cold water would lead to a stuck fly sparge. Can you explain your reasons for believing this might happen?

One benefit of hot water for either batch or fly sparging is that the collected wort is hotter, and so can be heated to boiling faster. There is however little, if any, difference in the amount of energy required to reach the boil with hot or cold sparging, since you have to heat to get hot sparge water.

All that said, the OP never mentioned what sparge method they are using. I assumed, maybe incorrectly, that it was a batch sparge since tap water is being used.

Brew on

 

[lhommedieu]

I'm not as concerned with rinsing out sugars during the sparge, which will happen whether I use hot or cold water, as I am in building an efficient filter. I would think that colder water effects the fluidity of the sparge, as well as whether protein sludge is as apt to settle on top of the grain bed.

 

[doug293cz]

I'm not as concerned with rinsing out sugars during the sparge, which will happen whether I use hot or cold water, as I am in building an efficient filter. I would think that colder water effects the fluidity of the sparge, as well as whether protein sludge is as apt to settle on top of the grain bed.

I have seen it claimed (https://bsgcraftbrewing.com/Resources%5CCraftBrewing%5CPDFs%5CBrewing_Processes_and_Techniques/WortandBeerFiningManual.pdf) that the effects of higher sparge temps may not be as simple as we normally believe:



The coagulation mentioned might be the protein sludge that you are worried about. I'd like to see more definitive empirical evidence of the affect of temperature on sparge flow (anybody got any?)

Brew on

 

[guillaume]

Can't simply look up dilution of sugar in water vs temp to settle the matter?

 

[doug293cz]

Can't simply look up dilution of sugar in water vs temp to settle the matter?

You mean like this: http://chestofbooks.com/food/science/Experimental-Cookery/Solubility-Of-Maltose-In-Water-gillis.html

The solubility of maltose in water at 70°F works out to an SG of about 1.200. You'll never have enough sugar left in the grain bed after initial run off to get the SG of the sparge water anywhere near the solubility limit. And remember, the residual sugar in the grain bed is already dissolved, so your not trying to dissolve solid sugar in cold water.

The questions aren't really about sugar solubility, but rather does the water temperature affect the kinetics of the sparge. The answer for batch sparge is: no. The answer for fly sparge is: very likely.

Brew on

 

[pablosbrewing]

I'm not as concerned with rinsing out sugars during the sparge, which will happen whether I use hot or cold water, as I am in building an efficient filter. I would think that colder water effects the fluidity of the sparge, as well as whether protein sludge is as apt to settle on top of the grain bed.

Mash out step increases solubility, so temp does matter when fly sparging.

 

[doug293cz]

Mash out step increases solubility, so temp does matter when fly sparging.

References please. Explain to me why you need more solubility, when all of the sugar is already is solution? It is in solution when it is created, and at mash temps, you have enough solubility to keep more that 16 lb of maltose dissolved in 1 gal of water (wort with an SG of about 1.347.) See the link in my previous post.

Hot water matters in fly sparging because you are depending on diffusion to mix the wort retained in the grain with the sparge water, and diffusion happens faster at higher temperatures.

Brew on

 

[pablosbrewing]

References please. Explain to me why you need more solubility, when all of the sugar is already is solution? It is in solution when it is created, and at mash temps, you have enough solubility to keep more that 16 lb of maltose dissolved in 1 gal of water (wort with an SG of about 1.347.) See the link in my previous post.

Hot water matters in fly sparging because you are depending on diffusion to mix the wort retained in the grain with the sparge water, and diffusion happens faster at higher temperatures.

Brew on

Some of the sugar is still inside the grain until you raise the temperature it cannot easily be rinsed out... just one reference to start off with:

http://www.howtobrew.com/section3/chapter17.html

Edit: If the sugar was already all in solution, fly sparging would have no benefit.

 

[grrickar]

So how hot is too hot when fly sparging? I tried it, and efficiency gains were not seen. I sort of do a hybrid now, I fly sparge about half the water, close all valves, stir everything (I use a Wilser BIAB bag for a liner in my cooler), vorlauft, then open valves and proceed with final fly sparge and slow lauter. I am wondering if hotter water will rinse the grains better. I'm usually at 170F+ or thereabout.

 

[doug293cz]

Some of the sugar is still inside the grain until you raise the temperature it cannot easily be rinsed out... just one reference to start off with:

http://www.howtobrew.com/section3/chapter17.html

Edit: If the sugar was already all in solution, fly sparging would have no benefit.

So, I went back and reread the section of How to Brew that you linked. Couldn't find anything in there that contradicted what I said. Can you point out the part that you think does contradict what I said? The grain bed is kind of like a sponge. If you dip a dry sponge in water, and then remove it, some of the water drains off and some remains in the sponge. If you dipped the sponge in sugar water, then some of the sugar would be retained in the sponge along with the water, but this doesn't mean that the sugar has entered the cellulose of the sponge, it's just trapped in the pores and still dissolved in the water. Same with sugar in wort retained in the grain bed. It's dissolved in the water.

As to your Edit question, let's assume we are making a 5 gal batch with 12 lbs of grain, and that the weighted average of the grain potentials is 1.036. We then have 12*36 = 432 potential gravity points, So, if we could actually get 5 gal of wort with all of the available sugar, we would have an SG of

1 + 432 / (5 * 1000) = 1.0864.​

Now an SG of 1.0864 converts to Plato as 20.51. Thus our 5 gals of wort would have:

0.2051 * 1.0864 *8.329 *5 = 9.2634 lb of sugar​

If we used 1.5 qt/lb of strike water we would have

1.5 * 12 = 18 qts or 4.5 gal of strike water​

If we got 100% conversion efficiency, then the wort in the mash would have:

4.5 * 8.329 = 37.48 lb of water​

and

9.2634 lb of sugar​

The wort would be

9.2634 / (9.2634 + 37.48) = 0.198176 => 19.8176% sugar or 19.8176 Plato
19.8176 Plato converts to an SG of 1.083​

The total volume of wort in the mash is

(9.2634 + 37.48) lb / (1.083 * 8.329 lb/gal) = 5.18 gal​

If we have a typical apparent grain absorption of 0.125 gal/lb, then we would have

12 * 0.125 = 1.5 gal apparent absortion​

So, if we ran off all of the wort in the MLT without fly sparging, we would collect

4.5 - 1.5 = 3.0 gal​

But the actual volume of wort in the mash was 5.2 gal so the real grain absorption was:

5.18 - 3.0 = 2.18 gal of 19.8176 Plato wort​

This 2.18 gal of retained wort is 19.8176% sugar by weight (19.8176 Plato) so the amount of sugar retained in the wort is

0.198176 * 2.18 * 1.083 * 8.329 = 3.897 lb​

The sugar collected in the BK would be

0.198176 * 3.0 * 1.084 * 8.329 = 5.363 lb​

Without sparging we would be leaving

3.897 / (3.897 + 5.363) = 0.4208 => 42.08%​

of the sugar we created in the mash as wort held in the grain bed, and our efficiency would only be 57.92%. We need to sparge to get more of this sugar out of the grain bed and into the BK. Either fly sparging or batch sparging would dilute the wort in the grain bed, and the sparge run off would contain most of the remaining sugar in the wort retained in the grain bed. Since we have collected more of the sugar by sparging, our efficiency went up.

Brew on

 

[doug293cz]

So how hot is too hot when fly sparging? I tried it, and efficiency gains were not seen. I sort of do a hybrid now, I fly sparge about half the water, close all valves, stir everything (I use a Wilser BIAB bag for a liner in my cooler), vorlauft, then open valves and proceed with final fly sparge and slow lauter. I am wondering if hotter water will rinse the grains better. I'm usually at 170F+ or thereabout.

You didn't see efficiency gains compared to what? Sparging of any type always increases efficiency compare to not sparging. Although in certain cases (like full volume mashing with bag squeezing in BIAB) the sparging gains in efficiency may be minimal.

Brew on

 

[C-Rider]

I BIAB and grind my grain down to flour. Not worried about "stuck" anything w/BIAB.

 

[guillaume]

doug, that's one awesome answer as to how sparging works.

 

[doug293cz]

doug, that's one awesome answer as to how sparging works.

Thanks. Once I started to understand whats going on with the sugar balance in the mash, I found it fascinating. It's actually a little more complicated than in my explanation above, but the errors from what I left out are small compared to the measurement errors for things like volume and grain potential, so don't significantly affect the numbers.

Brew on

 

[pablosbrewing]

Hi Doug,
Apologies - this is what I was initially challenging:

all of the sugar is already is solution?

It isn't all in solution. Sugars are still trapped in the gelatinous (not liquid) part of the mash.

Mash out changes the viscosity (I used the word solubility) of the gelatinous part of the mash - what you can reasonably extract is affected by this.

Cheers

 

[doug293cz]

Hi Doug,
Apologies - this is what I was initially challenging:



It isn't all in solution. Sugars are still trapped in the gelatinous (not liquid) part of the mash.

Mash out changes the viscosity (I used the word solubility) of the gelatinous part of the mash - what you can reasonably extract is affected by this.

Cheers

For solutions of just sugar and water, viscosity does decrease with increasing temperature. However, wort is not just sugar and water. A mash contains proteins and other components in addition to sugar, water, grain husks, non-starch endosperm bits, etc. According to the Wort and Beer Fining Manual, page 6 (https://bsgcraftbrewing.com/Resources%5CCraftBrewing%5CPDFs%5CBrewing_Processes_and_Techniques/WortandBeerFiningManual.pdf) increasing temperature may actually increase the wort viscosity, thus hindering lautering.

"Coagulation of mash particles is favoured by an increase in final mash temperature, though this may also increase wort viscosity, which will tend to offset the beneficial effects of coagulation on run off rates."​

I'd like to see some real data on mash viscosity vs. temperature over the 140° to 175°F range.

Gelatinous materials are made up primarily of water, and that water can have other compounds dissolved in it. In order to create sugar from starch, you have to have water present, as each maltose molecule cleaved from the starch chain has to pick up a molecule of water as part of the reaction. No water, no sugar converted. The starch to sugar conversion reaction takes place surrounded by water, and the newly created sugar molecules don't spontaneously precipitate into crystalline sugar, they stay in solution. The fact that this solution may be within a gelatinous matrix makes no difference. The gelatinous matrix is a very porous structure, so relatively small molecules can diffuse easily into and out of the gelatin "globs." The presence of large starch molecules increases the viscosity of the wort, but as starch to sugar conversion proceeds, the viscosity drops rapidly. The gelatinous masses that are held together primarily by proteins will grow softer and more porous as the starch is converted to sugar. The less dense the gelatinous globs are, the faster water and sugar can diffuse in and out of them, and the faster the saccharification reactions can proceed.

I stand by my assertion that all sugar created in a mash is in solution. The fact that the solution may be part of a gelatinous blob is immaterial (except as it may affect diffusion rates.)

Brew on