Adding salt to beer makes the pH goes down?

This may seem like a strange question, but I'll explain why afterwards.

Is it normal for the pH of a beer to go down when you add salt to it? The pH measured at about 4.1 on an electronic pH meter. After I added some sea salt to a sample, it dropped to around 3.5.

Is this to be expected?

I wouldnt think the seasalt would make the pH drop. Natural seawater has a pH of ~7.9-8.3 depending on where it comes from. The bicarbonate within seawater has a buffer capacity which would make the pH increase. There is nothing that I can think of within seawater/seasalt that would cause the pH to decrease.

Certain calcium compounds (e.g. CaCl2 in sea salt) can liberate hydrogen ions reducing the pH. So, yes it is plausible.

I would think Sodium Bicarbonate would be more abundant, which would act as a buffer

Sea salt is ~98% NaCl. The remaining percent is small amounts of calcium sulfate (gypsum), magnesium chloride, calcium chloride, sodium sulfate, etc. The gypsum and calcium chloride can both reduce pH. I don't believe there is [virtually] any sodium bicarbonate in unadulterated sea salt.

However, 4.1 to 3.5 is a big drop, so assuming the meter to be correct, perhaps there is something else going on like CO2 coming out of solution and carbonic acid.

Well, the beer was completely flat (no carbonation) when I added the salt, so I don't think it is because of carbonic acid being released.

The reason I am salting beer is because I am using it as a schmear for a washed-rind cheese.

btw, mods... This might be a thread that is appropriate for the new brewing science section.