Is Snape really THAT good in Potions?(was: Snape and the Kappa)

[nkafkafi]

No: HPFGUIDX 119376


After Nora found a textbook example that Snape might not be such an
expert in DADA as he is cracked up to be, I had a REALLY strange
thought: Why do we all assume that Snape is such a wiz in Potions?
I've raked my brains, and as far as I can remember the only canon
source for that is Lupin, who tells Harry in PoA that the Wolfbane
Potion is very complex and very few potion masters are up to it. Can
someone corroborate Snape's expertise from a different source?

After all, the fact that a teacher calls his students "idiots" doesn't
automatically means that he is an expert. And the fact DD hired him is
also not much of a proof, considering DD also hired Trelawney and some
not-terribly-competent DADA teachers.

Ha, I know - he prepared Veritaserum and it did make Crouch Jr
confess. The proof is in the pudding! But did Snape really prepare
that Veritaserum? Somehow we all assume he did, but I couldn't find it
in canon. DD asks him to bring "the strongest Truth Potion you
possess" (GoF, Ch. 35). "Possess" and not "prepared". Snape himself
only claims to prepare the Veritaserum in OotP, which turned out to be
fake.

And assuming for a moment he did brew the Veritaserum in GoF, are we
told that only the best experts can brew Veritaserum? Snape says that
it is controlled by very strict Ministry guidelines, and apparently it
takes a lot of time (and work?) to produce a very small amount, but is
it written anywhere that it takes a REAL expert? If so, I couldn't
find it.

Hmm. Would someone talk me out of this? 

I'll find it strange if Snape's reputation as a genius potion master
would depend solely on Lupin's word. And, since we (well, most of us)
know how kind and generous Lupin usually is, are we so sure that he
wasn't just a bit overgenerous to Snape here? It does look like he was
trying to make amends with Snape for most of the PoA year, calling him
pleasantly "Severus" and mostly overlooking Snape sneering at him. And
just when praising Snape he was also pointedly ignoring Harry trying
to suggest that Snape is not to be trusted.

And of course, if Lupin is ESE we definitely should not take his word
if it cannot be corroborated anywhere in canon. He might have some
ulterior motives.

And BTW, how do we know that Snape is such a superb Occlumens? Oops,
Lupin again. Do I detect a pattern here?

Neri