How much yeast is enough???

[bgarino]

I have been searching recipes and have noticed that some call for two packs of Wyeast liquid yeast... Why?? Do you need more for higher gravity?

 

[dregus]

you need a healthy starter of yeast for high gravity beers so they do not stall out or sufficate. Honestly, I use a starter for everything. I use white labs liquid yeast and make starter from the 5mL tube. Generally though you only need a starter for high gravity beers but make sure that your wort is aerated thoroughly.

 

[Hex23]

Yes, generally need more yeast for higher gravity and lagers. You can use multiple packs or alternatively you can make an appropriate sized starter. I think I remember hearing on the Brew Strong Podcast, that the Wyeast activator packs are good for pitching to 5 gallons of 1.040 ale. The pack says up to 1.060, but I think the difference is in what one says is "the pitching rate recommended by professional brewers". www.mrmalty.com has lots of good information on this topic, including starters and a nice calculator for determining how many packs or how big of a starter.

 

[sjbeerman]

I would always make a starter when using liquid yeast regardless of the OG. The viability of the yeast can vary depending on the production date, whether it travelled to you during warm weather (if ordered through the mail), and other factors. Therefore, it is always safer to make a starter. In some cases, you may find it easier to pitch more vials or smack packs, but you still may not get complete attenuation. For example, I pitched 3 vials for one of my brews and I still ended with a stuck fermentation. In hindsight, I should of made that starter..