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We've recently started tracking pH more closely for our brewing liquor at different stages and vessels, in an attempt to understand a bit better how this all works and we have a few (for us) intriguing numbers that I hope some of you from the community might be able to shed some light on...
We have our water analysed on a quarterly basis with fairly consistent pH coming in to our site.
Water comes in at pH 7.5 to pH 8.0. We now measure raw liquor from our CLT just before knockout or when we're filling up the HLT. The numbers we're getting in the last month or so (since we started doing this) range from 7.10 to 7.94
We've also been taking readings of the HLT post-treatment. And the numbers that got us thinking are related to one agent we add to the HLT - a blend of sulphuric (5 - 10%) and hydrochloric acid (1 - 5%) from one of our suppliers. The addition volume is 1.7 litres to a 5,000 litre-HLT.
The addition process is straight-forward (the day before we brew) and takes into account full recirculation in the HLT before we take any readings the following day. The readings we got were roundabout pH 3.70 (which is the reason we decided to monitor this more closely).
We contacted our supplier to check that this was normal as we didn't expect to see such a low reading to be frank. Their technical dept came back stating that the blend's target was to lower alkalinity levels, rather than adjusting pH (I get it that they're not one and the same, but I'd have guessed that lowering alkalinity levels would result in a lower pH too by default, but happy to be corrected on this).
Anyway, brewing with this liquor resulted in mash start pH (15 minutes in), first and last runnings pH readings all consistently within our parameters, nothing out of the ordinary at all.
Then out of the blue we had one brewday where the CLT readings were still within the range above (7.90), but the same liquor once in our HLT post-treatment was at pH 6.24. Same addition of our blend of acids. Readings throughout the brewday were still pretty much the same as before, nothing that stood out as unusual.
On one hand we're happy with our readings throughout the brewday and throughout fermentation - no reason for concern here. On the other hand we felt a bit weird insomuch as we'd like to understand why we're seeing that 3.7 or thereabouts, which is a first for me. And finding out why we suddenly got such a different post-treatment reading would be nice too, moreso given that pH through the rest of the brewday was matching our expectations.
We treat only the amount of liquor we use on that particular brewday - in the sense that we don't compound additions to the HLT. The left-over liquor is pumped out to be used in other areas of the brewery. We start with an empty HLT for a new brewday.
The other addition on this water profile is made to the grist and before sparging, it's a blend of calcium sulphate and calcium chloride.
These readings were done with more than one pH meter, and both are calibrated on a daily basis. The samples are allowed to reach ambient temps before us taking readings.
Any pointers would be greatly appreciated.
We have our water analysed on a quarterly basis with fairly consistent pH coming in to our site.
Water comes in at pH 7.5 to pH 8.0. We now measure raw liquor from our CLT just before knockout or when we're filling up the HLT. The numbers we're getting in the last month or so (since we started doing this) range from 7.10 to 7.94
We've also been taking readings of the HLT post-treatment. And the numbers that got us thinking are related to one agent we add to the HLT - a blend of sulphuric (5 - 10%) and hydrochloric acid (1 - 5%) from one of our suppliers. The addition volume is 1.7 litres to a 5,000 litre-HLT.
The addition process is straight-forward (the day before we brew) and takes into account full recirculation in the HLT before we take any readings the following day. The readings we got were roundabout pH 3.70 (which is the reason we decided to monitor this more closely).
We contacted our supplier to check that this was normal as we didn't expect to see such a low reading to be frank. Their technical dept came back stating that the blend's target was to lower alkalinity levels, rather than adjusting pH (I get it that they're not one and the same, but I'd have guessed that lowering alkalinity levels would result in a lower pH too by default, but happy to be corrected on this).
Anyway, brewing with this liquor resulted in mash start pH (15 minutes in), first and last runnings pH readings all consistently within our parameters, nothing out of the ordinary at all.
Then out of the blue we had one brewday where the CLT readings were still within the range above (7.90), but the same liquor once in our HLT post-treatment was at pH 6.24. Same addition of our blend of acids. Readings throughout the brewday were still pretty much the same as before, nothing that stood out as unusual.
On one hand we're happy with our readings throughout the brewday and throughout fermentation - no reason for concern here. On the other hand we felt a bit weird insomuch as we'd like to understand why we're seeing that 3.7 or thereabouts, which is a first for me. And finding out why we suddenly got such a different post-treatment reading would be nice too, moreso given that pH through the rest of the brewday was matching our expectations.
We treat only the amount of liquor we use on that particular brewday - in the sense that we don't compound additions to the HLT. The left-over liquor is pumped out to be used in other areas of the brewery. We start with an empty HLT for a new brewday.
The other addition on this water profile is made to the grist and before sparging, it's a blend of calcium sulphate and calcium chloride.
These readings were done with more than one pH meter, and both are calibrated on a daily basis. The samples are allowed to reach ambient temps before us taking readings.
Any pointers would be greatly appreciated.
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