I have read about some of the belgian yeasts fermenting better after their first fermentation. This photo shows some yeast which was split between starters and stepped up, with the majority used, then replenished withe fresh wort. my bucket is filled to 4 gallons (4-5inches of head space) and the lid nearly blew off.

here's a boring 1 min video of the kreusen peeking out of the airlock.
Peter Gabriel in the background
http://www.herflyawaymanner.com/3787-bucket.AVI





the kitty likes the dried sweet (yet bitter) wort on the sides of the fermenter.

LOOK AT THAT YEAST!


Not to mention it's throwing sulphur big time
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so we had some people over and I was asked to move all my beer crap. I moved my 7-8 gallons of belgian style ale to the basement. Since it was chugging along really well. that carboy filled up to the top with kreusen, but it was way too cool in basement, in the morning it was about 60 degrees, bummer- the 3787 likes it 65+ so I brought it all upstairs and used a heating pad to bring them back to life. The carboy has filled up with foam once again. and they are bubbling again so hopefully i didn't piss them off too much.
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You'll find that the "better" fermentation is not because it is its second batch per se but it's more active because the amount of yeast that was pitched.

Now there are comments out there about how some flavorful yeasts (we're not talking 1056 here) change their flavor profile with subsequent pitching. This is likely from the stress the yeast goes through in fermenting. For instance, I have been told that 3068 (weizen) produces less amyl acetate (banana) on subsequent pitching and more clove (I forget the phoenol name). This I have experienced first hand. Some Belgian yeasts are particularly susceptable to this phenomena.

Dave Logsdon (sp?) and Chris White both talk about temperatures and quantity of yeast being pitched as well as wort gravity all affecting the flavor profile of a yeast. Since homebrewers generally don't put a yeast through mulitple ferments, we don't see this as much unless you look for it.

One myth that gets a lot of play in homebrewing is that yeasts like 3068 are more active than other yeasts. I believe this is do to the fact that they are used in specific types of beers that have strong head forming characteristics. Examples are Weizens and Stouts. I doubt it has anything to do with the yeast.