Poor Fermentation

[orlando]

The whole point of these vials is that they are designed to work pitched straight from the vial. They cost twice as much as dried yeast for that very reason.

So the marketing will have you believe. Experience tells us perform a starter to determine viability and to grow more cells than are available in the vial, even a single vial only contains 100Bn cells fresh from the factory, whereas a normal 23L batch of ale requires 150-200Bn cells at the correct pitching rate, given that yeast dies with time and handling you can see why a starter is pretty much essential. 'Good practice' is what I'd call it.

Very much agree that you need to make a starter with these vials. You don't know how they've been handled during shipping....or even at the homebrew shop. You could have a vial that is only 50% viable or less.

The main benefit is reviving the surviving yeast. The takeup of sugars, nutrients, oxygen and production of sterols all improve cell health. The downside is it needs to go into a huge amount of "wort" to double the number of cells, i.e. close to your your starting wort, which is a little too late.