Yeast Question

Australia & New Zealand Homebrewing Forum

Help Support Australia & New Zealand Homebrewing Forum:

lukec

Well-Known Member
Joined
23/4/10
Messages
231
Reaction score
69
I know that a Wyeast has 100 billion cells in a pack.

If i make a 1 litre starter it gives me and extra 150 billion, does that mean i now have 250 billion or have i just increased the amount by 50 billion.
 

np1962

It's all about the Beer
Joined
21/10/08
Messages
1,618
Reaction score
10
Location
Blakeview, SA
I know that a Wyeast has 100 billion cells in a pack.

If i make a 1 litre starter it gives me and extra 150 billion, does that mean i now have 250 billion or have i just increased the amount by 50 billion.
a. You only get 100bn cells in a pack produced today. Depending on age and storage conditions you will have less than this.

If we assume the pack is around a month or so old and kept well
Added to 1L of starter wort and left to ferment you will have a total of around 150bn cells.
This same starter on a stirplate will give you closer to 400bn cells.

A well kept 3 month old pack will contain around 59bn viable cells.
Smacking the pack does not increase the cell count.

Nige
 

Pennywise

Brewin' Beer for Crazy Clowns & Juggalo's
Joined
11/5/08
Messages
4,311
Reaction score
14
Depending on the viability of the pack, how old it is etc.. From a fresh pack I wouldn't think you'd get much, if any growth in a 1L starter, and if you did it would be minimal, though I guess you'd get more growth if using a stirplate. I split my packs up in to 5-6 vials and make a 1L starter from that
 

donburke

Well-Known Member
Joined
18/1/09
Messages
1,395
Reaction score
107
Added to 1L of starter wort and left to ferment you will have a total of around 150bn cells.

This same starter on a stirplate will give you closer to 400bn cells.
is the growth that much more on a stirplate ? i didnt realise it increased the growth rate by that much
 

argon

firmitas, utilitas, venustas
Joined
8/5/09
Messages
2,994
Reaction score
125
is the growth that much more on a stirplate ? i didnt realise it increased the growth rate by that much
Yep... consider a starter for a lager

20L of 1060OG Simple Starter requires = 4.93L
20L of 1060OG Stir Plate Starter requires = 1.85L

Much more achievable
 

np1962

It's all about the Beer
Joined
21/10/08
Messages
1,618
Reaction score
10
Location
Blakeview, SA
is the growth that much more on a stirplate ? i didnt realise it increased the growth rate by that much
Depending on which calculator you use, this was just a quick estimate using Beersmith which is probably top end.
For clarity using a stirplate should give between 250 and 400bn cells depending on which calculator you use/believe.
Nige
 

MaltyHops

Well-Known Member
Joined
21/1/10
Messages
870
Reaction score
93
is the growth that much more on a stirplate ? i didnt realise it increased the growth rate by that much
Going from what I've lightly read, the constant stirring in a striplate helps to
get more oxygen mixed into the wort - more than just a still wort container,
less than using airstones - and the amount of oxygen in wort determines how
much yeast reproduce.

Yeast will keep reproducing if oxygen is available and then switch mode to
producing alcohol when oxygen is all used up (and there's more sugars to
feed on).
 
Top