I am wondering if there is any benefit to adding an extra pouch of wyeast? Does it get the job done quicker? Does it make the beer stronger? Does it affect the taste?
Anyone have experience in this?
Yes, there are many benefits. No, it's not quicker. No, it doesn't make the beer stronger. Yes it affects the taste.
In general, a fresh Wyeast pouch as barely enough yeast to ferment 5 gallons of 1.050. But sometimes, yeast gets older or has been mistreated. Sometimes a brewer has 5.25 of a 1.055 batch.
Almost always, it's recommended to make a starter with liquid yeast, especially if a beer is 1.040 or above. Instead of making a starter, alternatively you can use two packages of yeast.
Proper pitching rates really are crucial to making the best beer you can. Mrmalty.com (Jamil Zainasheff) has a great write up on liquid yeast, proper pitching rates, and so on, so I won't go into it all right now except to copy a brief part:
A Wyeast Activator pack (the really big ones) and the pitchable tubes have an average of 100 billion cells of 100% viable yeast. The smaller packs are around 15-18 billion cells. You would need 2 of the large packs if you were pitching directly into 5.5 gallons of 1.048 wort to get the proper cell counts.
and (also from the same site):
The general consensus on pitching rates is that you want to pitch around 1 million cells of viable yeast, for every milliliter of wort, for every degree plato. A little less for an ale, a little more for a lager. George Fix states about 1.5 million for a lager and 0.75 million for an ale in his book, An Analysis of Brewing Techniques. Other literature cites a slightly higher amount. I'm going with Fix's numbers and that is what the pitching calculator uses.