Concentration levels for yaest starter

[Simon David kelly]

I've got a packet of Wyeast swelling ready for saturday brew day. I'd like to create a larger volume of yeast and would like to know what the right water volume would be, and sugar concentration, to get the best results by Saturday afternoon.

Cheers

Si

[Karle]

Is it ale or lager yeast? Is it activator or propagator? Are you brewing a standard 20 litre batch?

Here is a link that's helpful for starters: http://www.mrmalty.com/calc/calc.html

The recommended gravity for a starter is 1.030-1.040.

[Simon David kelly]

So I'll need about 1.5 lts of starter at say 40.

Will this have enough time to get up to a good size by Saturday, if I have it well oxigenated, with a pinch of yeast food and give it a swirl a few times a day?

[Mike Neilson]

Yeah cell count will be up, but you will have to pitch the whole starter as it would not of had the chance to flock out.

[Karle]

Yes, I would say so. It's the way I usually do it, prepare the yeast starter on Thursday evening and then pitch it Saturday afternoon. The yeast count in the starter is highest after 24 to 36 hours. I think if you were very precise then you would pitch the starter when it is at high krausen. However, that might be hard to determine since sometimes there isn't much krausen at all in my experience. Oxygenation makes a big difference, so swirling it often is a good idea (unless you've got a stir plate). Also keeping it warm, around 25 degrees is good.

[Simon David kelly]

Excellent ....

Hate to drag this out, but what's the best way to oxigenate if I have no pure oxygen on hand? A good shake of the starter before pitching from the packet ok?

[Karle]

Yeah, shaking it very well does the trick. I usually try to shake it for 5-10 minutes, it's good exercise too.