Mash pH vs. Sparge pH

Blackmuse

Well-Known Member
Lifetime Member
Established Member
Joined
Jul 8, 2012
Messages
1,242
Reaction score
1,687
Points
113
Location
Maine
Anyone know why the calculator states that for the mash, along with grains, minerals (calcium etc.) that adding 2ml of lactic acid will help bring me down from 6.5 to 5.4 pH BUT I only need to add .5ml (1/2ml) to my sparge water to get it from 6.5 to 5.5.....

It doesn't seem to make any sense!
 
Anyone know why the calculator states that for the mash, along with grains, minerals (calcium etc.) that adding 2ml of lactic acid will help bring me down from 6.5 to 5.4 pH BUT I only need to add .5ml (1/2ml) to my sparge water to get it from 6.5 to 5.5.....

It doesn't seem to make any sense!

What are the volumes you're using to calculate this? If you've got a larger volume of water in the mash than in the sparge, you'd need more acid.
 
What are the volumes you're using to calculate this? If you've got a larger volume of water in the mash than in the sparge, you'd need more acid.
It doesn't seem to matter the volume but I typically prep 4-5 gallons of sparge water and my mash water is typically in the same area (9 gallons of water total typically).
 
Takes more acid to move the pH of the buffered mash than the unbuffered sparge water? I see this all the time in my brewing.
I am glad that it is common I guess then it means I must not be doing anything wrong!...

But doesn't it seem odd? - It takes more acid to acidify water that is already being acidified by malts and additional minerals than it does to water that has no malts or additional minerals? in
 
I am glad that it is common I guess then it means I must not be doing anything wrong!...

But doesn't it seem odd? - It takes more acid to acidify water that is already being acidified by malts and additional minerals than it does to water that has no malts or additional minerals? in
The minerals in the malt and mash act as resistance to changes in the pH. In chemistry terms it referred to as the buffering capacity of a solution.

From wikipedia, "Buffer capacity is a quantitative measure of the resistance to change of pH of a solution containing a buffering agent with respect to a change of acid or alkali concentration"

The greater the buffering capacity the more acid/base is needed to change the pH. It works similarly with temperature as well, a sugar solution or salt solution takes more energy to heat up than a pure water solution due to the heat capacity.
 
There's also the logarithmic scale coming into play (but only a little bit in your example).
 
The minerals in the malt and mash act as resistance to changes in the pH. In chemistry terms it referred to as the buffering capacity of a solution.

From wikipedia, "Buffer capacity is a quantitative measure of the resistance to change of pH of a solution containing a buffering agent with respect to a change of acid or alkali concentration"

The greater the buffering capacity the more acid/base is needed to change the pH. It works similarly with temperature as well, a sugar solution or salt solution takes more energy to heat up than a pure water solution due to the heat capacity.
Thank you so much for this explanation!
- You have no idea how many times I have read about water, pH and minerals and have read almost your exact words but it went right past me! It took the words with the experience for it to click I guess! It finally makes sense!
 
Nothing like the moment of the epiphany!
 

Back
Top