A simple Model for pH Buffers - Revision history

Kaiser: /* Mash pH and Adjustments */

2011-01-31T04:04:55Z

‎Mash pH and Adjustments

Kaiser: moved Visualizing pH Buffers with a Simple Model to A simple Model for pH Buffers

2011-01-25T01:39:40Z

moved Visualizing pH Buffers with a Simple Model to A simple Model for pH Buffers

Kaiser at 01:38, 25 January 2011

2011-01-25T01:38:40Z

Kaiser: /* Visualizing pH and pH buffers */

2011-01-25T00:14:03Z

‎Visualizing pH and pH buffers

Kaiser: /* Visualizing pH and pH buffers */

2011-01-25T00:13:48Z

‎Visualizing pH and pH buffers

Kaiser: /* Visualizing pH and pH buffers */

2011-01-25T00:13:29Z

‎Visualizing pH and pH buffers

Kaiser: /* Visualizing pH and pH buffers */

2011-01-25T00:13:04Z

‎Visualizing pH and pH buffers

Kaiser: /* pH and buffers */

2011-01-25T00:09:23Z

‎pH and buffers

Kaiser at 00:08, 25 January 2011

2011-01-25T00:08:09Z

Kaiser: /* Visializing pH and pH buffers */

2011-01-25T00:07:02Z

‎Visializing pH and pH buffers

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 ==Mash pH and Adjustments==
-In mash the malt is the dominant pH buffer not only because it represents the largest amount of pH active substances but also because the water's carbonate buffer has almost completely been exhausted at commonly found mash pH values.
+In mash the malt is the dominant pH buffer not only because it represents the largest amount of pH active substances but also because the water's carbonate buffer has almost completely been exhausted at commonly found mash pH values. The pH buffers in malt are mainly phosphates, proteins and amino acids.
 Combining pH active substances like malt, water salts and additional acid is equivalent to connecting tubes of various shapes that represent the pH characteristic of these substances. Figure 4 Brings together a grist that has a natural pH of 5.75 (pilsner malt for example) with high alkalinity water. High alkalinity means that this water can absorb a lot of free hydrogen ions from the malt. The result is a mash pH that lies between the pH of the water and that of grist. Since the malt is the more strongly buffered substance the resulting mash pH (6.0) is closer to the pH of the malt (5.75) than the pH of the water (7.0) rise in pH once both systems are connected, I.e. water and malt are mixed at dough-in.

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 {| style="width:800px"
+|
 The understanding of pH buffers is critical for making sense of pH changes in mash, wort and beer.  To most brewers the fundamentals that are associated with pH are not as intuitive as they are for example for temperature. Temperature is something we can feel and we have learned over time, through experience, how it is affected and how changes can be predicted and controlled. This is not the case with pH, which we can neither feel nor see and for which we have developed little intuition. This article tries to illustrate the concept of pH buffers and how they interact with acids and bases with the use of a simple model.

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 The ability of a pH buffer to supply hydrogen ions when needed or absorb them when there are too many is best visualized as the water level in vertical tubes which differently shaped bulges that create reservoirs of varying capacity. The water level represents the pH and the size and location of that reservoir represents the buffer capacity which is a property of the solution and depends on the weak acids and bases present in that solution.
-When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sup>+<\sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
+When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sup>+</sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
 [[Image:PH_buffer_analogy.gif|frame|right|Figure 1: Models for 3 different pH buffer systems. See text for explanation]]

@@ Line 13: / Line 13: @@
 The ability of a pH buffer to supply hydrogen ions when needed or absorb them when there are too many is best visualized as the water level in vertical tubes which differently shaped bulges that create reservoirs of varying capacity. The water level represents the pH and the size and location of that reservoir represents the buffer capacity which is a property of the solution and depends on the weak acids and bases present in that solution.
-When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sub>+<\sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
+When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sup>+<\sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
 [[Image:PH_buffer_analogy.gif|frame|right|Figure 1: Models for 3 different pH buffer systems. See text for explanation]]

@@ Line 13: / Line 13: @@
 The ability of a pH buffer to supply hydrogen ions when needed or absorb them when there are too many is best visualized as the water level in vertical tubes which differently shaped bulges that create reservoirs of varying capacity. The water level represents the pH and the size and location of that reservoir represents the buffer capacity which is a property of the solution and depends on the weak acids and bases present in that solution.
-When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sub>+</sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
+When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sub>+<\sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
 [[Image:PH_buffer_analogy.gif|frame|right|Figure 1: Models for 3 different pH buffer systems. See text for explanation]]

← Older revision	Revision as of 01:39, 25 January 2011
(No difference)

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 =Visualizing pH and pH buffers=
-The ability of a pH buffer to supply hydrogen ions when needed or absorb them when there are too much is best visualized as the water level in vertical tubes which differently shaped bulges that create reservoirs of varying capacity. The water level represents the pH and the size and location of that reservoir represents the buffer capacity which is a property of the solution and depends on the weak acids and bases present in that solution.
+The ability of a pH buffer to supply hydrogen ions when needed or absorb them when there are too many is best visualized as the water level in vertical tubes which differently shaped bulges that create reservoirs of varying capacity. The water level represents the pH and the size and location of that reservoir represents the buffer capacity which is a property of the solution and depends on the weak acids and bases present in that solution.
-When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the pH and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
+When water is added the water level, as observed in a sight glass, for example, rises. The amount by which is rises depends on two things: the amount of water added and the diameter of the vertical tube at the current water level. The wider the tube the more water is takes to achieve the same water level change. This is very similar to pH in buffered systems. The water level is the H<sub>+</sup> concentration, which is expressed as pH, and the diameter of the vertical tube is the buffer capacity of the system which depends on the current pH. Adding water is analogous to adding hydrogen ions (i.e. adding acids).
 [[Image:PH_buffer_analogy.gif|frame|right|Figure 1: Models for 3 different pH buffer systems. See text for explanation]]

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 = pH and buffers =
-The chemical fundamentals of pH were discussed in [[An Overview of pH]]. There we saw that pH refers to the concentration of free hydrogen ions (H<sup>+</sup>) and that pH buffers are created by weak acids and bases which donate or absorb hydrogen ions depending on their current concentration in the environment, i.e the current pH.
+The chemical fundamentals of pH were discussed in [[An Overview of pH]]. There we saw that pH refers to the concentration of free hydrogen ions (H<sup>+</sup>) and that pH buffers are created by weak acids and bases which are able to donate or absorb hydrogen ions depending on the current concentration of these ions in the environment, i.e the current pH.
 =Visualizing pH and pH buffers=

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 [[Image:Work_in_progress.jpg]]
-The understanding of pH buffers is critical for making sense of pH changes in mash, wort and beer.  To most brewers the fundamentals that are associated with pH are not as intuitive as they are for example for temperature. Temperature is something we can feel and we have learned over time, through experience, how it is affected and how changes can be predicted and controlled. This is not the case with pH, which we can neither feel nor see and for which we have developed little intuition. This article tries to illustrate the concept of pH buffers and how they interact with acids and bases using a simple model.
+The understanding of pH buffers is critical for making sense of pH changes in mash, wort and beer.  To most brewers the fundamentals that are associated with pH are not as intuitive as they are for example for temperature. Temperature is something we can feel and we have learned over time, through experience, how it is affected and how changes can be predicted and controlled. This is not the case with pH, which we can neither feel nor see and for which we have developed little intuition. This article tries to illustrate the concept of pH buffers and how they interact with acids and bases with the use of a simple model.
 = pH and buffers =