Very Basic Yeast Starter Question

[hobospy]

OK starter for ten, I've read a good number of the yeast starter threads now and I am still a bit confused. When everyone talks about a 2l, 3l or 4l yeast starter does that mean that you harvest the yeast that you get from 2l, 3l or 4l of wort and not that you need 2l, 3l or 4l of actual yeast? I'm about to brew my first Bock which will be the first time I will be using a liquid yeast (WLP833), I've got a stir plate and 3l flask to help kick the yeast into gear but just wanted a bit of clarification as I will be pitching at low temperatures and want to ensure fermentation starts relatively quickly.

Thanks,

Christopher

 

[Eagleburger]

What you first said.

 

[hobospy]

Thanks Eagleburger , I know it was a very basic question but just good to get it clarified.

 

[squirt in the turns]

What's your batch size? For a "standard" batch of about 20 litres of standard gravity wort, a 5 litre starter is normally recommended. You get away with a smaller starter by pitching warm (maybe 19°C) and bringing the batch down to the desired fermentation temperature over a couple of days, which will help the yeast to multiply, but will probably require warming up again a little for a diacetyl rest before it hits FG.

This is rather general advice for lagers. Check the White Labs website for more specific info WLP833 and maybe do some Googling to see what fermentation temperatures others have had success with and what kind of propensity this strain has for throwing diacetyl.

Also check the Mr Malty calculator to work out how big a starter you need to make.

 

[hobospy]

I was planning on making quite a strong Bock (ESB 3kg can). Believe the suggested amount is about 15l but I'm not sure what SG that would give, guessing quite high. Thought I read somewhere that if you were using a stirring plate it could be possible to kick a lager off with 2l of starter, I was aiming at pitching nearer the 10-13 deg suggested fermentation temperature to try and avoid any funky flavours.

I'll have a look at the calculator too, first time nerves and all that.

 

[Spiesy]

What's your batch size? For a "standard" batch of about 20 litres of standard gravity wort, a 5 litre starter is normally recommended. You get away with a smaller starter by pitching warm (maybe 19°C) and bringing the batch down to the desired fermentation temperature over a couple of days, which will help the yeast to multiply, but will probably require warming up again a little for a diacetyl rest before it hits FG.

This is rather general advice for lagers. Check the White Labs website for more specific info WLP833 and maybe do some Googling to see what fermentation temperatures others have had success with and what kind of propensity this strain has for throwing diacetyl.

Also check the Mr Malty calculator to work out how big a starter you need to make.

You would also need to take into account the viability of your yeast.

No point making a 5L starter of dead yeast.

 

[hobospy]

Haha, yeah, the yeast is out mid December so I'm hoping that the vial is OK, from what I've read I might want to step the starter but not everyone thinks so, aiming to use a 100g LME per litre of water, using a stirring plate and all should be OK after 48hrs, still not sure how I'm supposed to judge when it is ready :S

 

[MartinOC]

Can you "step" your starter on the stir-plate?

If you can do a small one (ie. 250-500ml) to get things going for 48 hrs, that's a bonus. Then step-up to your required volume of starter wort. 'Makes sure you have active yeast before you commit a full batch.

 

[hobospy]

Maybe I'm misunderstanding what 'stepping' means but from my understanding it is just a matter of making a smaller amount of wort, getting the yeast resulting from that and using it in a larger amount of wort? How would a stir plate stop me from doing that? Was hoping to use a glass or something similar with the smaller size and then my flask with the 2 litre batch. Was actually hoping to step up to 3l and then keep some of the "spare" yeast for future brews.

 

[TheWiggman]

Stepping is necessary when making big starters or when starting with a small amount of yeast. Think of it as a ratio of wort to yeast - the more (healthy) yeast you add, the more wort can be used to propagate your yeast. If half of it's viable, then you want half the wort you'd normally use for the first 'step'.
If you have an in-date yeast which has been handled well and a stir plate, then 2l is ideal for the first pitch in a batch of 23l at 5% lager.
If you're suss about it, mix 500ml with the 10:1 ratio like you said, and give it a day to kick off. If it's going gangbusters, top up to 2l with 1.5l:200g of wort which has been boiled for 15 mins and cooled.

*Add disclaimer here about all the variables and there are always exceptions*

Dive in there and see how you go. I've learnt a lot from errors.

 

[hobospy]

Thanks for that Wiggman, the Bock is supposed to end up around 8-10% I think, should I be increasing the ratio of LME to water for the starter to get the yeast used to the wort I will be pitching into?

 

[TheWiggman]

Ooooh... that's territory I haven't ventured.
If my memory serves me it doesn't hurt to increase the SG a bit on the starter for a stronger beer (say 1.050) but you don't want to go too high. You're trying to make yeast, not beer. The more healty yeast you have the better. If you go too strong or too weak with the starter, the yeast either get stressed (too strong) or lazy (too weak).

Someone else who's done a Bock may know better. You'll definitely want a big starter though, in the 5l region.