Silver_Is_Money
Larry Sayre, Developer of 'Mash Made Easy'
In astronomy things such as magnitudes and distances are measured via the assistance of association with what are referred to as "Standard Candles".
With AJ deLange having stated that in his opinion the downward shift in pH within the mash is only on the order of 50-60% of what Kolbach had determined, and with Braukaiser (Kai Troester) in general agreement with AJ on this (albeit to a lesser degree than 50-60%), but with others (Martin Brungard and I believe DM Riffe also) accepting Kolbach at full value a "Standard Candle" is needed whereby to determine the correct answer.
I may have found one. Within Charles W. Bamforth's peer reviewed document titled "pH in Brewing: An Overview" such a standard candle may be found within the statement that "Taylor reports a lowering of pH in wort from 5.51 to 5.1 by increasing the level of calcium from 50 to 350 ppm." Bamforth's reference for this indicates that D.G. Taylor made this statement in 1990 within a document titled "The importance of pH control during brewing. MBAA Tech. Quart. 27: 131-136". This presumably independently derived observation of measured pH drop under the influence of increased calcium can be seen as a "Standard Candle" by which to test Kolbach.
But first, there is a catch. The problem with pH drop in association with ppm's of calcium within mash water is such that a mash thickness value and mash water volume must be assigned to it, as for example a 12 Lb. Grist mashed in 4.5 gallons of water (a mash thickness of 1.50 quarts per pound, or ~3.13 Liters per KG) at 50 or 350 ppm respective calcium would exhibit only 25 or 175 ppm calcium respectively if the same grist was to be 'no-sparge' mashed within 9 gallons of water. PPM is thereby a highly faulty means by which to approach the problem, and mEq's of calcium (and magnesium) are the solution to counter this weakness, as mEq's are independent of mash water volume. Now back to the story...
It turns out that for a mash in the mash thickness ballpark of roughly 1.5 quarts per pound (roughly 3 Liters per Kg.), and with buffering such that a composite grist that has an initial DI_pH of 5.58 falls to a pH of 5.51 when in the presence of 50 ppm of added calcium, will subsequently only exhibit a drop from 5.51 to ~5.1 (and thereby agree with D.G. Taylor) if Kolbach's calculated pH drop formula is taken at full 100% face value within the mash.
There are a lot of if's and presumptions being made here with respect to Taylor's observation, and there is also the possibility that Taylor merely used Kolbach's formula rather than independently measuring a drop from 5.51 pH to 5.10 pH when calcium was increased from an initial 50 ppm to a final 350 ppm, and we don't know the buffering nature of Taylor's grist or his chosen mash thickness, but if the general presumptions which I've made here stand and Taylor observed this fully independent of Kolbach, then Kolbach's observed pH drops which were measured downstream at "knock-out" are also fully valid for computing pH drop within the mash as well. And therefore so is Kolbach's formula derived to math-model the same.
I had formerly sided with only 50% of Kolbach in my most recent 'version 8.01' series release of 'Mash Made Easy', but with the D.G. Taylor "Standard Candle" to go by I will correct this to 100% in the soon to be released MME version 8.10.
With AJ deLange having stated that in his opinion the downward shift in pH within the mash is only on the order of 50-60% of what Kolbach had determined, and with Braukaiser (Kai Troester) in general agreement with AJ on this (albeit to a lesser degree than 50-60%), but with others (Martin Brungard and I believe DM Riffe also) accepting Kolbach at full value a "Standard Candle" is needed whereby to determine the correct answer.
I may have found one. Within Charles W. Bamforth's peer reviewed document titled "pH in Brewing: An Overview" such a standard candle may be found within the statement that "Taylor reports a lowering of pH in wort from 5.51 to 5.1 by increasing the level of calcium from 50 to 350 ppm." Bamforth's reference for this indicates that D.G. Taylor made this statement in 1990 within a document titled "The importance of pH control during brewing. MBAA Tech. Quart. 27: 131-136". This presumably independently derived observation of measured pH drop under the influence of increased calcium can be seen as a "Standard Candle" by which to test Kolbach.
But first, there is a catch. The problem with pH drop in association with ppm's of calcium within mash water is such that a mash thickness value and mash water volume must be assigned to it, as for example a 12 Lb. Grist mashed in 4.5 gallons of water (a mash thickness of 1.50 quarts per pound, or ~3.13 Liters per KG) at 50 or 350 ppm respective calcium would exhibit only 25 or 175 ppm calcium respectively if the same grist was to be 'no-sparge' mashed within 9 gallons of water. PPM is thereby a highly faulty means by which to approach the problem, and mEq's of calcium (and magnesium) are the solution to counter this weakness, as mEq's are independent of mash water volume. Now back to the story...
It turns out that for a mash in the mash thickness ballpark of roughly 1.5 quarts per pound (roughly 3 Liters per Kg.), and with buffering such that a composite grist that has an initial DI_pH of 5.58 falls to a pH of 5.51 when in the presence of 50 ppm of added calcium, will subsequently only exhibit a drop from 5.51 to ~5.1 (and thereby agree with D.G. Taylor) if Kolbach's calculated pH drop formula is taken at full 100% face value within the mash.
There are a lot of if's and presumptions being made here with respect to Taylor's observation, and there is also the possibility that Taylor merely used Kolbach's formula rather than independently measuring a drop from 5.51 pH to 5.10 pH when calcium was increased from an initial 50 ppm to a final 350 ppm, and we don't know the buffering nature of Taylor's grist or his chosen mash thickness, but if the general presumptions which I've made here stand and Taylor observed this fully independent of Kolbach, then Kolbach's observed pH drops which were measured downstream at "knock-out" are also fully valid for computing pH drop within the mash as well. And therefore so is Kolbach's formula derived to math-model the same.
I had formerly sided with only 50% of Kolbach in my most recent 'version 8.01' series release of 'Mash Made Easy', but with the D.G. Taylor "Standard Candle" to go by I will correct this to 100% in the soon to be released MME version 8.10.
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