Yeast for 1 Gallon brew

[winstonia]

Got a few demijohns and want to experiment.

How much dried is used per batch, guessing 2.2 grams.  Any else do these brews?

[DEMPSEY]

Your typical pack of yeast is 11.5 g and it is often assumed that 1 pack is suitable for brewing 20 to 30 litres,however this is not accurate. 3 packs are usually best needed for Lagers as there simply is not enough yeast in 1 pack so I would say it depends on  the brew

[LordEoin]

yeah, totally depends on the brew but for something like nottingham or us05 etc where you know 1 pack does 5 gallons properly  I'd generally split into 4 because it's easy (half then half).
For lagers when it recommends 2 packs per 5 gallons, half a pack per gallon will be fine.

[winstonia]

Just in general, if it recommends 2 packs for 5 gallons. Could you make a starter with one to increase the cell count and just use 1 pack or still need two + starter....

[Parky]

I brew small batches of 5L - 10L and have found that 4g of rehydrated yeast works well for a 5L demijohn. I've got a jewellers scales that allows me to weigh out 4g, but failing that LordEoin's technique will work just fine too.

See this video for some good advice on small batch brewing - https://www.youtube.com/watch?v=O6etLNVq7p4

One little tip when pitching into a demijohn is to fill the demijohn maybe 3/4 the way up. Shake the wort for a few minutes to aerate (don't forget to sanitise whatever you've got over the top of the demi), and when the foam has subsided enough, pitch the yeast. Add a cover on the demi (the airlock or sanitised tinfoil) and wait for the foam to dissipate before topping up with the rest of the wort. Doing this will allow you to aerate the wort quite well, but will also mean that you're not pouring the yeast into foam that's trying to escape the demi (been there, bought the t-shirt  )

An advantage of using a demijohn is that there's very little headspace, but just be aware that if filling up to 5L you may need a blow-off tube during primary fermentation, as the yeast gets very excited and wants to come out and play