Yeast consistency.

[TheRedDarren]

I'm currently reading a lot about top cropping, or harvesting in general, and pitching rates.
I think I'm ok on most of it but one thing I keep reading concerns me a bit and that's consistency of flavour.
I understand that a vial from a supplier is a very pure culture and at the other end of the scale a badly harvested sample that has been badly kept is very different indeed.
How obvious is that difference in flavour? Has anyone noticed a difference?

I guess it might be less obvious in a neutral strain with a lot of other flavours for instance in an IPA compared to a Belgian ale which is very yeast forward.
I'm just a bit worried that's saving a few quid on liquid yeast is going to have a detrimental affect on flavour.

 

[clibit]

If you handle yeast carefully, sterilise everything, and pitch enough yeast, it will behave fine.

 

[Simonh82]

You can reuse yeast multiple times and as long as your sanitation is good you should be fine. As I understand it, traditionally people have said 5-6 repitches was enough and that will certainly save you money but you can extend this by overbuilding and harvesting from your starter, rather than from the fermentation vessel. This Brulosophy article explains it and suggests you can get to 13 generations http://brulosophy.com/methods/yeast-harvesting/.

I think the issue with repeated harvesting from your fermentation vessel can be two fold. Firstly there is more chance of picking up bugs and wild yeast over the course of multiple brews. The second is the tendency for yeast strains to drift if their characteristic over multiple repitches. For instance if you repeated harvested from the krausen of a top cropping yeast, over time the yeast may become less flocculent, conversely, if you always harvested from the slurry at the bottom of a fermentation vessel the yeast may become too flocculent and prone to settling out early.

These issues are somewhat negated by harvesting from a starter as it is easier to maintain good sanitary conditions over the few days a starter is being made and you can easily cold crash it and harvest almost all of the yeast rather than just from the top of the bottom.

 

[mike77]

I collect a big jar of yeast from the bottom of the primary and store it. Then when I want to ise it I build a starter from it. I get several starters off one jar so I'm not going multiple generations.