Kit Yeasts

[Adamt]

Assuming the yeast is in decent shape after being strapped to a can for a long truck ride, a long sit in a warehouse and a long sit on the shelf under possibly some rather ordinary conditions, is probably a little optimistic.

 

[PostModern]

I find no problems with underpitching. I regularly pitch half a packet of Fermentis yeast and keep the rest sealed in the fridge. I make up 500ml of 20 degree water with a few spoons of dextrose and let it start feasting for an hour - but I don't think it's doing much cellular division then.

I do aerate my wort though. It's always bubbling happily within 12 hours.

Doesn't the yeast spend the first few hours dividing until the population is balanced with the food source - regardless of how much you pitch?

The only dry yeast I use with any regularity is US-05. It has no yeast character. For an extra $2, I don't mind saving 12 hours lag time to get a clean beer.

MrMalty calculator says you only need 10g of dried yeast for 20L or 1.050 wort. I think it's ridiculous to pitch 23g of yeast (2 saf packs) into a standard wort, one is more than enough, since most 'standard' wort is 1.045-1.048.

7g isn't that much of an underpitch imo, as long as the yeast is in decent shape.

Regardless of what that website says (12-14g for a typical brew at my house), I think most homebrewers underpitch dry yeast and get used to the taste of stressed yeast. 50-80g per HL is the recommended pitching rate for commercial beer for Fermentis yeasts, so I don't see that 2 extra grams is much of an overpitch for a neutral yeast with almost no lag time and plenty of healthy cells left to repitch.

1.055 is a standard beer for me (many of my brews are above this), which might account for my habit of pitching lots.

 

[Nick JD]

The only dry yeast I use with any regularity is US-05. It has no yeast character. For an extra $2, I don't mind saving 12 hours lag time to get a clean beer.

If I use the whole 11g it still takes 12 hours to start bubbling ... and I don't notice the difference in taste (no less estery - but I do like a fruity ale B) ) with identical recipes and brew temperature. To be honest, when I first started extract brewing after coming from decades of awful K&K, I looked on the Fermentis packet, saw 11g and thought, "this must be for two brews, I'll fridge the other half."

The difference is probably much more apparent if one has no O2 in their wort at pitching and the yeast can't multiply.

I'd be interested to know how many cells are pitched at the start, compared with how many have lived and died over the fermentation period ... I have a feeling we're pitching a tiny fraction of the eventual colony - and when growth is exponential (replication by division) starting with 10, or starting with 1000 doesn't really make any difference.