Water Chemistry And Mash Ph

[mesa]

Hi All,
I've been becoming interested in my water chemistry and specifically my mash pH. I've got the 2008 water report for my area of sinkas, and I've got hold of Palmers spreadsheet for calculating additions etc. I plan to get some pH indicator before the next brew tomorrow arvo.

I can understand that phosphates will be released from malt and react with Ca/Mg ions to reduce the buffering capacity as well as releasing hydronium ions to lower the pH (assuming the buffering capacity is taken up). What I don't understand is why
a) This calculations appears to be independent of the grain to water ratio (I would have though a stiffer mash would produce a higher concentration of phosphate and suck up the buffering capicity faster. I'm usually at a ratio of about 2.1L/kg to fit a mash for a 40L batch in a 55L esky)
B) How Palmer magically converts a residual alkalinity to an SRM/EBC colour value. I'm left guessing that this is an empirical measurement of what EBC will produce an appropriate pH for a given residual alkalinity, but then I'm back to the question of what water/grain ratio is used to get this result.

Has anyone got more detailed info than Palmer? Or should I just stop being a nerd playing with theory and trust the experimental results?

--
Mesa.

 

[matti]

Have a read of Gregory Noonans How to brew lager Beer.
He goes through the water analysis a bit.

This calculations appears to be independent of the grain to water ratio (I would have though a stiffer mash would produce a higher concentration of phosphate and suck up the buffering capicity faster. I'm usually at a ratio of about 2.1L/kg to fit a mash for a 40L batch in a 55L esky)

With a thicker mash you'll have a more dextrinous wort as the enzymes for conversion stay more powerful.
I.e getting to the starches easier.

This will not happen as efficiently unless the pH is adjusted to suit enzymatic activity.

Or should I just stop being a nerd playing with theory and trust the experimental results?

Yes!
I don't know what your water is like, But if it hasn't got many buffer in it initially you can get away brewing any ale.
If you try to brew lager it is essential you try to adjust pH to 6.8 or below for soft water and lower for hard water.

BTH I look it up so I'd get my facts right

 

[beers]

B) How Palmer magically converts a residual alkalinity to an SRM/EBC colour value. I'm left guessing that this is an empirical measurement of what EBC will produce an appropriate pH for a given residual alkalinity, but then I'm back to the question of what water/grain ratio is used to get this result.

Has anyone got more detailed info than Palmer? Or should I just stop being a nerd playing with theory and trust the experimental results?

--
Mesa.

Hey mesa,

I believe he uses the colour of the final beer, as opposed to mash, in his calcs. See here - http://www.thebrewingnetwork.com/forum/vie...?f=2&t=8762
You could try PMing him (username: howtobrew on the brewing network forum) for more detail if you need it I guess.

Cheers

 

[mesa]

Thanks guys,
I think I'm going to get a copy of Noonan's book.
Since Palmer himself says its all about arm waving, perhaps I won't think too much more about it.
--
Mesa.

 

[goatherder]

Mesa, I found Noonan's book very good in it's treatment of water chemistry concepts and the effects of the different ions on beer. However, it talks nothing of residual alkalinity and is more from the school of matching chemistry to famous locations. I feel Palmer's approach is the better one. That being said, Noonan's book is still a very good reference for water chemistry and many other topics.

It's a good point you raise about the water to grain ratio, I'm not sure how that should be treated. I think the answer to it lies in your second question - how does Palmer convert RA to a colour value? I suspect it was the result of a experimental testing, and the large range of colours for a given RA shows how much error there actually is in this method. I think that variations in the water to grain ratio are probably well within the error limits of the RA ranges for a given colour. Arm waving is an excellent description, I've found it's like that when brewing using RA calcs.

The other point I'll mention is that mash pH is more important for getting the final beer pH correct rather than optimising the enzymatic conditions. The enzymes will still work through a range of pH environments even though they might not be at their optimum point. The pH of the final beer is important as it helps to present the right balance of flavours to the drinker. Check out this episode of Basic Brewing Radio where Palmer runs an experiment with beers which were deliberately made to have the wrong finishing pH: http://media.libsyn.com/media/basicbrewing...2-07styleph.mp3

 

[dr K]

We can, and do tinker at the edges of water chemistry in brewing, we are lucky that the very components within the mash make a great buffer, we are also lucky that most of us don't use bore water so its pretty hard to screw up really badly.
I am happy to talk generally about salt additions but am lost in a world of RA/Apparent Hardness/Alkalinity/PH balance..
Basic advice for the new brewer do not worry, for the more advanced..well a tablespoon of Gypsum for ales, CaCl for lagers or CaCO3 for darkies will not go astray..just one small point as well

With a thicker mash you'll have a more dextrinous wort as the enzymes for conversion stay more powerful.
I.e getting to the starches easier.

Wrong way round, and remember as well for the enzymes to work on the starches they must first be gelatinised..

K

 

[matti]

Wrong way round, and remember as well for the enzymes to work on the starches they must first be gelatinised..

Right way around!
It is true that the pH is not essential for conversion but it is a good idea to check it.
Listening to Goat herder link as I type.

Probably the best explanation I've 'heard in one hit regarding Residual Alkalinity "the balance of the mineral in the water"
pH and brewing to style.

It is the formula 1 of brewing.
This is diving into the murky water of the dark side and come yp with clean tasting beer.

I get you Dr K

 

[amiddler]

I have always mashed with a grist to water ratio of 3.5 thinking the good range was 3 - 4L/Kg. Was now thinking of doing my next brew with 2.8 - 3L/Kg. What differences should I see from this change? The brew will be a basic Lager of 100% Lager Malt bittered to 25 IBU, 34/70 Lager yeast. I have made it a few times when supplies get low.

Am I right to think that with less water the mash will be of a lower Ph? If so what benefits will my final beer have from this. I currently don't monitor my Ph so water adjustments are something I have never played with.

Drew

 

[Wolfy]

I have always mashed with a grist to water ratio of 3.5 thinking the good range was 3 - 4L/Kg. Was now thinking of doing my next brew with 2.8 - 3L/Kg. What differences should I see from this change?

As per the 3rd paragraph here: http://www.howtobrew.com/section3/chapter14-6.html

3-4L/kg is typically in the 'thin mash' range (~1.75-2 Qt/lb), 2.8-3L/kg is just on the 'stiff' side of what is generally recommended as 'ideal' (1.5Qt/lb = 3.13L/kg).
Lowering the water/grain ratio (could do 2.0-2.6L/kg for a stiffer mash) means you should end up with a sweeter and maltier beer due to the change in concentration of enzymes.

 

[MHB]

Generally lighter and paler thinner, heavier and darker thicker mashes

Lager can be mashed at up to 5:1 (old school brewing) and one recipe for a very heavy stout was mashed in at ~2.1:1 and then there were several additions of near boiling water to get sharp temperature steps.

Here in Newcastle we are lucky to have dam near perfect waterthat requires very little TLC, but the more I tinker with water chemistry the more I think Residual Alkalinity is the key concept to get your head around.

MHB

 

[Sammus]

Generally lighter and paler thinner, heavier and darker thicker mashes

Lager can be mashed at up to 5:1 (old school brewing) and one recipe for a very heavy stout was mashed in at ~2.1:1 and then there were several additions of near boiling water to get sharp temperature steps.

Here in Newcastle we are lucky to have dam near perfect waterthat requires very little TLC, but the more I tinker with water chemistry the more I think Residual Alkalinity is the key concept to get your head around.

MHB

I'm loving water chemistry. You may remember Mark years ago I was having shocking efficiency problems.. it took me way too long to realise that wollongong water is ridiculously soft and is pretty much devoid of calcium, which I understand is fairly important for the enzymes present in the mash. A small calcium addition and my efficiencies shot up a consistent 20% across the board. Light, dark, whatever.

 

[goatherder]

I'd argue that you won't see any detectable difference in your homebrew as a result of making such a change, even if you did a well designed blind tasting experiment. The difference won't be large enough to overcome your batch-to-batch variability.

If you want to change the malt profile & fermentability of your brew, first play with your grist composition and then with your mash temperature. Much bigger levers to pull.

As for your final questions, less water will not necessarily mean lower mash pH - it will depend on the mineral content of the water. I suspect that the liquor to grist ratio won't make a huge difference due to the buffering capacity of the mash. It's worth doing some pH measurements on your mash, just to find out if you are in the ballpark. If it isn't right, it can be an easy problem to fix, as Sammus has described. Also, if you find out it's OK, you can stop worrying about it & just make beer.

I have always mashed with a grist to water ratio of 3.5 thinking the good range was 3 - 4L/Kg. Was now thinking of doing my next brew with 2.8 - 3L/Kg. What differences should I see from this change? The brew will be a basic Lager of 100% Lager Malt bittered to 25 IBU, 34/70 Lager yeast. I have made it a few times when supplies get low.

Am I right to think that with less water the mash will be of a lower Ph? If so what benefits will my final beer have from this. I currently don't monitor my Ph so water adjustments are something I have never played with.

Drew

 

[hefevice]

[snip]
B) How Palmer magically converts a residual alkalinity to an SRM/EBC colour value. I'm left guessing that this is an empirical measurement of what EBC will produce an appropriate pH for a given residual alkalinity, but then I'm back to the question of what water/grain ratio is used to get this result.

Has anyone got more detailed info than Palmer? Or should I just stop being a nerd playing with theory and trust the experimental results?

--
Mesa.

I asked him a question about this (colour vs residual alkalinity) after his talk on the subject at the ANHC. It's totally empirical and a rough estimate at best, bearing in mind that you could arrive at the same colour with completely different types of malt (with different chemical compositions and affect on pH). At least it's somewhere to start.

I don't know for sure how sensitive the pH is to water/grain ratio, however I would not be surprised if it is relatively independent for the normal range of mash parameters. There is a possibility that some of the salts affecting the pH balance become more soluble at higher ratios which may compensate for the dilution effects. Best way to find out is to try a few test mashes.

Mashing is an extremely complex set of chemical processes - there are so many variables (many uncontrollable) and interactions that it is almost impossible to model it completely (nor is it useful).

 

[katzke]

a) This calculations appears to be independent of the grain to water ratio (I would have though a stiffer mash would produce a higher concentration of phosphate and suck up the buffering capicity faster. I'm usually at a ratio of about 2.1L/kg to fit a mash for a 40L batch in a 55L esky)

Has anyone got more detailed info than Palmer? Or should I just stop being a nerd playing with theory and trust the experimental results?

Mesa.

Well I will take a stab at this.

Not only does he not take into account the water to grain ratio he does not even take into account the amount of grain you will be using.

It has been a while since I have rummaged around and looked at the calculations as they bore me to death. I was fairly good at math however somehow got through school with zero chemistry. That said I seem to recall that the calculations may be based on an assumption of gravity. One thing to remember is the calculation of RA is not Palmers. It is based on the work done by Paulas Kohlbach. If you read the about page in the excel sheet you do find that the calculations are based on estimates and guesses. I find the results are very good for being based on estimates and guesses.

Now as to why water to grain ratio would not be important. The calculations are based on water volumes. No other way to calculate how many PPM of CA you have in your brewing water unless you know how much water you have. If the grain weight were important, then it would be asked for. The ratio would not be important, as it would not have any direct influence (You will see in figure 3 of the link below my guess is close).

Now why is the grain weight not asked for? I have no idea. My guess is because the pH range is logarithmic. Or a pH of 6 is not one bigger then a pH of 5 but 10 times different. When you play with the addition of salt you will see it takes quite a bit to make a change in RA. A 20 % difference in the grain bill may not make that much difference in the resulting RA.

Now if you were brewing a barley wine the results may be different. I have no idea as I have not brewed one. I do know that my very accurate color change pH test strips have been with in range for the beers I have brewed from 1.035 to 1.070. After writing this I may make some adjustments for high gravity brews to get them closer to my target.

Now that I wrote all this I found a web page that has some info on the subject. I think the results of their work say about the same thing I did that the gravity and water to grain ratio does have an effect. That effect is not all that important if some assumptions are made in the calculations. I have the program they developed. I have not played with it yet to see how different the results are to the Palmer calculations. Here is the link. http://www.braukaiser.com/wiki/index.php/B...ity_and_mash_pH