How much yeast to use?

[JohnRB]

I'm experimenting with different hops and grains using liquid malt extract as a base. Grains will be steeped in the kettle (a big pan) before adding the LME. Hops will be added at different times in the boil.

As some brews may 'fail' I plan to use a shorter brew length of 11 litres. Yeast will be from a small stock of 11g sachets of Safale US-05. As these were quite expensive I wonder if I can get away with half a sachet per brew??

Also to aid yeast propagation would it be a good idea to use a yeast starter especially if I can get away with half sachets?

Any advice most gratefully received.

John

 

[graysalchemy]

Firstly a quick question are you brewing these all at once so they will be all be at the same stage or are they going to be brewed over consecutive weekends?

If you brew one a week you stand a chance of using a yeast cake from the first for the second and so on, or even the yeast cake would probably do 2-3 batches.

If they are all going to be brewed over a short space of time make up a decent starter probably 3-4 L. Once it has fermented out take it of the wort and split it between you batches. Having said that you may as well use the first method as effectively the first one is a starter and use a whole packet to get it going.

:thumb:

 

[JohnRB]

Thanks for such a quick reply.

To answer your question I'll be brewing intermittently when I have time and fermentation space.

I like your idea of yeast cakes and that's certainly one for the future. At the moment though I already have two variables in the hops and grain used so I don't really want to introduce a third one in yeast cake.

So back to the original questions in an 11l brew do I still need to use a full yeast sachet? Would it make a difference if I prepared a starter? Maybe use half now and keep half in the fridge for a week or so. Advice gratefully received.

As an aside is there a reason why yeast comes in expensive sachets rather then (cheaper?) tubs?

Thanks.

 

[JohnRB]

Based on a couple of trial extract brews it seems that there is no problem in splitting and storing sachets of yeast.

Half a sachet went into an 11l pale ale brew a couple of weeks ago and in 6 days had fermented down to a target gravity of 1009. Abv is calculated at 3.9%.

The remainder was wrapped in foil and then cling film and stored on the top shelf of the fridge. After 2 weeks in the fridge it was pitched into 13l of IPA which has a target abv of 5.1%. After 12 hours there was a vigorous fermentation which is continuing.

In both cases the yeast was rehydrated prior to pitching.

In summary I'd have no worries about splitting and storing a yeast sachet in the future and it does make a useful cost saving.

 

[Belter]

Beersmith can answer this. There is a 'Starter' tab where you can calculate the amount of yeast you need for a brew.

 

[Good Ed]

Also you can use Mr Malty http://www.mrmalty.com/ go to the yeast tools and then the yeast calculator, I just put in 11L at OG 1048, which needs 5g of dry yeast ie 1/2 packet