Leftover liquid yeast

[jezbrews]

How long does it last? The liquid yeast bags seem excessive when I'm doing small batches (5L/1gal) to try out recipes, so I'll not need it all at once, can I keep it? If I could use a dry version of what I want I could, but I can't.

 

[An Ankoù]

I presume its a wyeast slap-pack or a WLP sachet?
Use it all. It won't keep easily and it won't be an over pitch.
Then, either top-crop the yeast from a thick head of yeast or keep the Lees after you've racked off the beer.
Keep them in a sterised flask or jar with a bit of aluminium foil on top, kept in place with a rubber band. Don't use an airtight seal like a screw top lid. When you're ready to pitch the new batch, open the jar, taste the beer on top of the yeast (it won't be great, but it shouldn't taste off) replace the foil and leave out of the fridge for it it reach room temperature. When you're ready to pitch, pour off most of the beer, swirl the yeast into the remaining liquid and pour into the wort. Use within a month. Two weeks is better.

 

[jezbrews]

I presume its a wyeast slap-pack or a WLP sachet?
Use it all. It won't keep easily and it won't be an over pitch.
Then, either top-crop the yeast from a thick head of yeast or keep the Lees after you've racked off the beer.
Keep them in a sterised flask or jar with a bit of aluminium foil on top, kept in place with a rubber band. Don't use an airtight seal like a screw top lid. When you're ready to pitch the new batch, open the jar, taste the beer on top of the yeast (it won't be great, but it shouldn't taste off) replace the foil and leave out of the fridge for it it reach room temperature. When you're ready to pitch, pour off most of the beer, swirl the yeast into the remaining liquid and pour into the wort. Use within a month. Two weeks is better.

Brilliant, thank you!