Can I make this assumption about magnesium?

[Underthethumb]

Hi,

i've received a water report from my local provider which has all the figures I need for GW's water treatment calculator except magnesium.

Given that GW says the 'initial ion balance check' should come out equal, I have made the Magnesium figure 5mg so that this is indeed the outcome.

Is this a reasonable thing to do?

Thanks in advance.

[mabrungard]

That assumption for Mg is appropriate and reasonable. That assumption is based on the rest of the ion concentrations being accurate, but at only 5 ppm Mg it is not a big deal.

That is a pretty good brewing water to start with...after alkalinity reduction. I see that you are leaning toward CRS and that could be fine in some styles. The resulting sulfate and chloride levels are getting up there, especially the chloride. The sulfate can go much higher with little penalty, but the chloride should be kept lower if the sulfate is going to be higher than shown above. That is the problem with CRS, you are stuck adding chloride and sulfate. That is not always ideal.

Since this water has such high Temporary Hardness, it is well suited to boiling for alkalinity reduction. That would significantly reduce the calcium content and the alkalinity. This would also leave the chloride and sulfate as they are (which is quite low). With that boiling treatment, the water is much more suited to lighter flavored styles that would benefit from the water just playing a supporting role. The calculator above may tend to guide users toward adding far too much mineral character to the water and that can affect beer flavor. If you like minerally flavor in your beer, using this approach will be fine. If you want the malt and hop flavor to shine more, then you may need to avoid recommendations to add high levels of these ions.

[Underthethumb]

That assumption for Mg is appropriate and reasonable. That assumption is based on the rest of the ion concentrations being accurate, but at only 5 ppm Mg it is not a big deal.

That is a pretty good brewing water to start with...after alkalinity reduction. I see that you are leaning toward CRS and that could be fine in some styles. The resulting sulfate and chloride levels are getting up there, especially the chloride. The sulfate can go much higher with little penalty, but the chloride should be kept lower if the sulfate is going to be higher than shown above. That is the problem with CRS, you are stuck adding chloride and sulfate. That is not always ideal.

Since this water has such high Temporary Hardness, it is well suited to boiling for alkalinity reduction. That would significantly reduce the calcium content and the alkalinity. This would also leave the chloride and sulfate as they are (which is quite low). With that boiling treatment, the water is much more suited to lighter flavored styles that would benefit from the water just playing a supporting role. The calculator above may tend to guide users toward adding far too much mineral character to the water and that can affect beer flavor. If you like minerally flavor in your beer, using this approach will be fine. If you want the malt and hop flavor to shine more, then you may need to avoid recommendations to add high levels of these ions.

I really appreciate your thorough response. Water treatment always seems such a complex area but I think if I can get it right it will make a big difference. Cheers