Splitting a pack of yeast?

[Wez]

I'm due to do a double brewday tomorrow but have just found out that i only have 1 pack of Safeale s-04 can i just split the pack and make two starters? If so should I make both up together with the wort from brew #1?

[steve_flack]

How strong are the beers and how much are you making?

To be honest you'd need a bloody big starter to grow 11g of safale to a bigger amount.

[tubby_shaw]

IMO using one pack of dried yeast split between 50 litres isn't going to be enough
Get a starter made up now to get the yeast multiplying overnight, then split that starter tomorrow and add some wort from your first beer to both halfs.
That should see you right

[Wez]

IMO using one pack of dried yeast split between 50 litres isn't going to be enough
Get a starter made up now to get the yeast multiplying overnight, then split that starter tomorrow and add some wort from your first beer to both halfs.
That should see you right

What should I make the starter up with? Talk me through that do I use some DME mixed with cooled boiled water?

[steve_flack]

The only way you're going to get any real growth out of 11g of yeast is to have starter of the order of a gallon or more. With a pint starter you are not going to get much growth.

For 20L of 1.040 you need 8g of yeast. With 11g in one beer you're actually overpitching a little. If you just rehydrate the pack and split it there you'll have 5.5g each of active yeast. That's only a little under the recommended pitching rate and well in excess of what most people pitch when the use liquid yeast and a starter.

[Wez]

How strong are the beers and how much are you making?

2 x 25L batches 1041 and 1043

[Wez]

The day is saved!

My mate has an unopened Woodfordes Kit that I can nab the yeast from, hopefully I won't get the 'stuck' problem. What do you think use the s-04 in one and the Woodies yeast in t'other?

[steve_flack]

In that case then each batch needs 10g. My point about the starter size still stands. I still think you'd be better off properly rehydrating the yeast and just splitting it. All you will do by making a small starter is use up all the trehalose that's built into the dried yeast cells. You might actually make things worse.

EDIT: When you think about it all you need is double the number of yeast cells. That's one extra time the yeast has to multiply. Yeast probably can do that in under an hour

[steve_flack]

What do you think use the s-04 in one and the Woodies yeast in t'other?

Yeah go for it. Problem solved

[tubby_shaw]

IMO using one pack of dried yeast split between 50 litres isn't going to be enough
Get a starter made up now to get the yeast multiplying overnight, then split that starter tomorrow and add some wort from your first beer to both halfs.
That should see you right

What should I make the starter up with? Talk me through that do I use some DME mixed with cooled boiled water?

Boil 500ml of water with 120g of dme.
Allow it to cool, aerate it, pitch the yeast.
Let it ferment under airlock preferably at a constant temp (20 to 22C)
This way you will have an actively fermenting yeast tomorrow that you can pitch into some of the wort from your first brew to allow it to grow a little more
As Steve says it is not the ideal way to go, but it will give you a workable solution

[Wez]

In that case then each batch needs 10g. My point about the starter size still stands. I still think you'd be better off properly rehydrating the yeast and just splitting it. All you will do by making a small starter is use up all the trehalose that's built into the dried yeast cells. You might actually make things worse.

The cuurent method I use to rehydrate is:

Get 50ml cooled boiled water to around 35 deg C mix 1/2 tsp ordinary sugar with it and add the dried yeast and mix well, after 20mins when it's trying to escape from teh 500ml PET bottle I add 250ml of the wort that it's going to be added to and agitate, then when it's started to ferement this it goes into the fermenter, is that right?

[Wez]

I don't think i've ever seen so many cross-postings - Steve & Tubby - many thanks!

[steve_flack]

Depending upon who you ask some say not to use sugar in the first step - just water. The thing is that when the dry cells hit the water the first time, they cannot control what crosses their cell membrane. So the risk of killing the cells with the sugar is a possibility if there's too much. Once the yeast is rehydrated then you can add wort and the cell walls are working properly.

[tubby_shaw]

I don't think i've ever seen so many cross-postings - Steve & Tubby - many thanks!

I need to drink less and type faster

[johnmac]

Steve, when I make a 10 gallon batch, I use one sachet of S04 to make a pint starter. There's active fermentation after two hours. If I simply sprinkle two sachets directly onto the wort, nothing happens for six hours.

That appears to contradict your advice, or have I got the wrong end of the stick, as usual?