why do yeast starters to 1.040 OG?

[TheH2]

Why not have higher OG and lower volume, i.e. .5 liter starter at 1.05? I can't imagine that this would stress the yeast and would allow you to pitch a sufficient amount of yeast without decanting.

What am I missing?

 

[hoplobster]

I can only assume that every "How to make a starter" discussion always insists on a 1.040 wort because anything higher is probably unnecessary, but I am fairly confident that a 1.050 starter would make beer that is just as good.

 

[david_42]

Because you are growing yeast and the lower gravity makes it easier for the yeast to absorb nutrients, so they grow faster. Growth is also oxygen limited & a higher gravity might make the yeast switch over to alcohol production. Then they'll have to switch back to growth when pitched.

 

[ChshreCat]

At higher gravities, yeast are more likely to start fermenting rather than reproducing. It's call the Crabtree Effect. Since the idea of a starter is to build up a good population of yeast cells, it makes more sense to have a gravity that is more conducive to that process.

 

[malkore]

Also, thicker worth can make it harder for yeast to wake up, especially dry yeast. The osmotic pressure is different in a thicker wort than a thinner wort.

 

[Piotr]

Actually, I usualy make 1.020 starters.