Are DO meters accurate for HSA?
Posted: Mon Aug 07, 2017 1:29 pm
After my potential false positive DO reading on my single vessel system (due to potentially not agitating the sample enough) I went to read up more on the tool.
I came across Fix's statement "DO meters are not suitable for measuring HSA, since on the hot side dissolved oxygen will react with wort constituents before it can be measured."
This coupled with the reductive tendency of the meter itself has me wondering if this is a good tool at all for hot side auditing. I seem to remember Nico stating he only used his on the cold side and had no intention of sticking it in the mash. In addition, I remember a buddy measuring a non-pre-boiled wort and having a surprising low DO reading.
Any thoughts? I'm wondering if taste, color, and perhaps sulfite test strips is a better approach to measuring HSA than my current process of pulling a sample, cooling, and measuring.
Fix then goes on to say:
"Time Test (ITT) is a good way to measure oxidation caused by HSA. The test measures the time, in seconds, for a solution of dichloro indophenol (DCI) to become discolored when beer is added. DCI exists in a highly oxidized state and will react with a color change when combined with a substance in a lower oxidation state. The speed of the color change is a measure of the substance’s degree of oxidation and varies from seconds for highly reduced solutions to hours for those having a significant amount of oxidized components. Easy-to-follow protocols along with criteria can be found in references 27 and 28. Special note should be made of the improved media recently recommended for this procedure (29)."
Never heard of this method.
The Source: https://www.morebeer.com/articles/oxidation_in_beer
I came across Fix's statement "DO meters are not suitable for measuring HSA, since on the hot side dissolved oxygen will react with wort constituents before it can be measured."
This coupled with the reductive tendency of the meter itself has me wondering if this is a good tool at all for hot side auditing. I seem to remember Nico stating he only used his on the cold side and had no intention of sticking it in the mash. In addition, I remember a buddy measuring a non-pre-boiled wort and having a surprising low DO reading.
Any thoughts? I'm wondering if taste, color, and perhaps sulfite test strips is a better approach to measuring HSA than my current process of pulling a sample, cooling, and measuring.
Fix then goes on to say:
"Time Test (ITT) is a good way to measure oxidation caused by HSA. The test measures the time, in seconds, for a solution of dichloro indophenol (DCI) to become discolored when beer is added. DCI exists in a highly oxidized state and will react with a color change when combined with a substance in a lower oxidation state. The speed of the color change is a measure of the substance’s degree of oxidation and varies from seconds for highly reduced solutions to hours for those having a significant amount of oxidized components. Easy-to-follow protocols along with criteria can be found in references 27 and 28. Special note should be made of the improved media recently recommended for this procedure (29)."
Never heard of this method.
The Source: https://www.morebeer.com/articles/oxidation_in_beer