Recent R&D has shown that there is no significant difference in fermentation performance between dry pitched and rehydrated yeast.
Dry pitching is the preferred method of inoculating wort. This method is simpler than rehydration and will give more consistent fermentation performance, also reducing the risk of contamination.
Rehydration of yeast prior to pitching should be used only when equipment does not easily facilitate dry pitching, for bottle conditioning and some fermentations other than beer.
Watch our Pitching Best Practice video to learn more:
FWIW - I recently pitched a packet of yeast into some chilled and well shaken wort (about a liter) and then an hour or so later, I poured it into the full batch. I observed no difference in any aspect of fermentation between that and sprinkling on the surface of the full batch. I don’t know why I even thought to try this, but I did. So, from now on (and as I have done routinely for the last 3 or more years) I will just sprinkle on the surface of the full batch of chilled wort and let it do its thing. Thanks for the definitive update.
We don’t recommend aerating the wort in normal conditions. The dry yeast has been produced and dried with a specific know-how of the Lesaffre Group, in order to maximize the Ergosterols content of the cells. This allows the yeast to grow/multiply and ferment well.However, you could aerate the wort in particular cases, for example if you recycle the yeast. There is no difference (for the O2) between Ale and Lager.
NOTE: if you recycle the yeast it essentially becomes liquid yeast and the appropriate procedures are recommended
