Can I model brewing grains as little sponges? sort-of ...

[p_p]

Hi all. I am trying to understand ion diffusion through brewing grains...
So If:

1\ I have a bucket which has a sponge and it and is filled with 2 volumes a water which has 100 ppm of an ion.
2\ I drain 1 volume of that water into a second bucket (the rest is taken by the sponge).
3\ I top up the first bucket with 1 volume of water which has 200 ppm of the same ion.
4\ I allow enough time for full diffusion to happen and I drain 1 volume into the second bucket.
=> I ended up with 2 volumes of water in the second bucket, with a concentration of 125 ppm of the ion.

What about now if the steps above are repeated, but the first bucket is filled with a quantity of brewing grains that absorbs 1 volume of water, instead of the sponge?

The problem I am trying to solve here is, from the point of view of ion concentrations & diffusion (and not pH regulation):

Is it the same to use two different waters (for mashing and sparging), than to use a single water, given the "sponge model above"?

Thanks.

 

[Skep18]

Um... What?

 

[brewfun]

I ended up with 2 volumes of water in the second bucket, with a concentration of 125 ppm of the ion.
<snip>
Is it the same to use two different waters (for mashing and sparging), than to use a single water, given the "sponge model above"?

What you're describing is titration.

The mechanics of your analogy are simple enough to explain concentrations of anything that's in an inert strata. The trouble is that malt isn't inert and various reactions take place that don't allow your analogy to work very well.

 

[p_p]

What you're describing is titration.

The mechanics of your analogy are simple enough to explain concentrations of anything that's in an inert strata. The trouble is that malt isn't inert and various reactions take place that don't allow your analogy to work very well.

Fair enough... If I would have named the ion as, lets say, Zn, the answer would have been yes. But if it was Ca or K, then the analogy is no good because these ions react with or are provided by the malt.

So when advice is given on water profiles for style ... How can you make sure your water is correct if your mash water has a different profile from the water you sparge with?

Lets say I brew a pale with RO.
I may initially add some Ca to the mash water. I wouldn't add any salts to the sparge water. And finally I may add some more salts to the kettle. How do I know what the overall water profile was in this case?

 

[brewfun]

So when advice is given on water profiles for style ... How can you make sure your water is correct

The total concentration of any ion is valued in milliequivalents (mEq.), which is the amount of any substance needed to combine with 1 mole of Hydrogen. This provides a baseline for comparison and answers the question of "how do you know," when differing amounts are added at different times.

The thing to remember, and help keep your sanity, is that water minerals are a range. When measured in a lab, the exact same water profile can have different measured outcomes in different recipes. Not to mention differences in flavor perception. Saying there is only one mineral combo of water for a style is pseudo-accuracy.

Hopefully, what you'll discover is that water mineralization is for flavor perception and yeast health. Hit those targets and you've achieved the goals of a beer style.

 

[SEndorf]

The total concentration of any ion is valued in milliequivalents (mEq.), which is the amount of any substance needed to combine with 1 mole of Hydrogen.

Brewfun, I value your knowledge which is formidable in chemistry as it relates to the brewing process. It also allows you to effectively answer questions such as these.

What gives me great comfort, are folks exponentially smarter than me who have developed tools which allow me to chemically alter my water profiles so I don't need to count moles of hydrogen......

 

[brewfun]

What gives me great comfort, are folks exponentially smarter than me who have developed tools which allow me to chemically alter my water profiles so I don't need to count moles of hydrogen......

There are plenty that are exponentially smarter than me, too. AJ and Martin could tie me up with a little bow on this subject.

This forum is for deep science, and still, I tried to simplify my explanation for readability. That said, even with tools, it's very useful to understand the theory behind them, which is what I believe the OP was trying to do. I learn something new about brewing science quite frequently and I respect anyone else trying to do the same.

 

[p_p]

The total concentration of any ion is valued in milliequivalents (mEq.), which is the amount of any substance needed to combine with 1 mole of Hydrogen. This provides a baseline for comparison and answers the question of "how do you know," when differing amounts are added at different times.

The thing to remember, and help keep your sanity, is that water minerals are a range. When measured in a lab, the exact same water profile can have different measured outcomes in different recipes. Not to mention differences in flavor perception. Saying there is only one mineral combo of water for a style is pseudo-accuracy.

Hopefully, what you'll discover is that water mineralization is for flavor perception and yeast health. Hit those targets and you've achieved the goals of a beer style.

Apologies to keep going at it, brewfun, but perhaps you can help me out with an example?

Lets say I have this water:
Ca 20
Mg 5
Cl 12
SO4 9

I use the same water for mash and sparging.
In the mash I have about 10 punds of grain. I use 3.5 gal of water and add 5gr of CaSO4.
For sparging I use 3.5 gal of water and I do not add any salts.
During boil I add 4gr of CaSO4 and 2gr of MgSO4.

What was my overall water profile in this case?

Note that I would like to know this to reference against recommended profiles and to be able to make adjustments in following batches of the same beer. Hence, an approximation would be sufficient since the data would be compared against data obtained using the same method.

Thanks again

 

[cilestiok]

Apologies to keep going at it, brewfun, but perhaps you can help me out with an example?



Lets say I have this water:

Ca 20

Mg 5

Cl 12

SO4 9



I use the same water for mash and sparging.

In the mash I have about 10 punds of grain. I use 3.5 gal of water and add 5gr of CaSO4.

For sparging I use 3.5 gal of water and I do not add any salts.

During boil I add 4gr of CaSO4 and 2gr of MgSO4.



What was my overall water profile in this case?



Note that I would like to know this to reference against recommended profiles and to be able to make adjustments in following batches of the same beer. Hence, an approximation would be sufficient since the data would be compared against data obtained using the same method.



Thanks again

To answer this you would need to know what mineral contributions your grains contribute.

 

[p_p]

To answer this you would need to know what mineral contributions your grains contribute.

Really? Because in all recipes posted in this and other sites which include recommended (or used) water profiles, I have never seen one that includes mineral contribution from malt. Instead, profiles are given for the totality of the brewing water.

I am not sure if I am failing to convey my question or final answer was given already by brewfun on his first reply.

 

[brewfun]

What was my overall water profile in this case?

I couldn't tell you. Your missing the alkalinity and the grist weight (as 100% base malt) and the water to grist ratio.

Once you have those, you can do the calculations yourself so that you understand the math of what you're asking. I can't do your homework for you.

Note that I would like to know this to reference against recommended profiles and to be able to make adjustments in following batches of the same beer.

In real world brewing, mineral calculations are based on all base malt for pH, then some adjustment can be made for specialty malts. I'm not going to go into specialty malt adjustments, just the base water.

In the mash, Ca & Mg react with malt phytin to neutralize some alkalinity. Kohlbach's research says that it takes 3.5 milliequivalents (mEq and that's per liter) of Ca reacting with phytin to lower one mEq of water alkalinity. With Mg, it takes seven mEq to lower one mEq of alkalinity.

After that reaction, what's left is residual alkalinity (RA), made up of unbuffered anions. The RA is the most important thing for brewers to consider when adding minerals or acids to adjust.

The calculation is:

mEq RA = mEq Alkalinity - [(mEq Ca)/3.5 + (mEq Mg)/7]

Volume is in liters.

Converting your incomplete numbers above, your baseline water had an RA of around -15.8 on my calculator and -17 in Bru'n Water's spreadsheet. This is enough to get you to around 5.6 mash pH.

Once you've determined how much Ca & Mg are needed for RA, you can subtract that amount from your totals.

The remaining minerals and how they bond with wort constituents, I don't have any calculation for. Only my taste perception. But, taste is what being a brewer is all about.

 

[cilestiok]

Really? Because in all recipes posted in this and other sites which include recommended (or used) water profiles, I have never seen one that includes mineral contribution from malt. Instead, profiles are given for the totality of the brewing water.



I am not sure if I am failing to convey my question or final answer was given already by brewfun on his first reply.

The reason I say this is because you added in the bit about mineral additions in the boil. Malt supplies minerals, acidity, etc. which affect yeast health, hot break, cold break, yeast flocculation, taste, etc. There is a lot more to it than just "overall water profile". We only have so much control over what passes on to the boil. And then after those additions, it is in the hands of the yeast to determine what carries on to the brew you drink. I believe you're chasing imperial data which will be unreliable at best. It is in our nature to pursue as much information as possible in order to control every aspect we can, but pursuing information that is unreliable is merely a witch hunt.

 

[p_p]

Thank you everybody.
This has been a very enlightening thread for me.

 

[cilestiok]

This thread has got me thinking what the relationships are between sparge efficiency and the carryover of minerals. If sugars are leftover in the grain bed after sparging, a certain percentage of minerals (from water and/or grain) must also be left over.

I know it sounds like I'm picking nits but if someone used the same recipe, batch sparging one time and fly sparging the next, would there be a different amount of minerals carried over to the kettle? Absolutely. Is it enough to make each respective batch taste different even if the gravities and volumes are the same? Doubtful.

And I believe that is a more direct answer to your initial question. It wasn't as much about grain being "little sponges" as much as it was about how much of your water chemistry carried over to the kettle.

 

[p_p]

This thread has got me thinking what the relationships are between sparge efficiency and the carryover of minerals. If sugars are leftover in the grain bed after sparging, a certain percentage of minerals (from water and/or grain) must also be left over.

I know it sounds like I'm picking nits but if someone used the same recipe, batch sparging one time and fly sparging the next, would there be a different amount of minerals carried over to the kettle? Absolutely. Is it enough to make each respective batch taste different even if the gravities and volumes are the same? Doubtful.

And I believe that is a more direct answer to your initial question. It wasn't as much about grain being "little sponges" as much as it was about how much of your water chemistry carried over to the kettle.

Exactly!

I had a quick look at brewersfriend. The water calculator indicates overall water profile as if all additions had been done to the total volume of water. The overall profile does not change whether the salts were added to the mash or directly to the kettle. As you said, the two methods would yield different beer albeit the difference may not be significant.