I suspect that this is to reduce the possibility of contamination of
your must. The pH meter tip may still be wet with storage solution, or,
if you've rinsed it with tap water, it may be harboring microbes.

It's just better not to stick anything into your must.

Greg

snpm wrote:
> Ken Schramm mentions (but does not explain why) he takes a small sample
> of must for pH sampling then ditches it. He says this is preferable to
> dipping your pH meter into the must in the primary fermenter.
>
> Can anyone tell me why?
>
> Thanks all,
>
> Sean