First up was Hop Back from a bottle of Summer Lightning. I've used this before and it grew well on the agar plate. My latest brew was made using this culture, and the fermentation went fine. Tasting notes will be posted when I start drinking it.
Next I cultured the sediment from bottles of Fullers 1845 and Sierra Nevada pale ale. The Fullers yeast has been depressingly feeble though.
You can just about make out two small yeast colonies, as well as a fungal contaminant and a bacterial contaminant at the top.
As I had to incubate the plate for so long some contaminants have started growing. With a bit of experience it's pretty easy to identify what's growing on your agar plate from the shape of the colonies without having to look at anything under the microscope. In this case though, as I had so little growth, I popped into the lab for confirmation.
Fullers yeast at x 1000 magnification
If you don't have a microscope set up with a camera you can take pictures by carefully holding a digital camera above the eye piece. The picture above was done on my mobile phone and you can just about see the yeast cells.
Here the bacterial contaminant - large rods of a Bacillus sp.
As I'm happy that even from the poor growth I have got some brewing yeast I've sub-cultured it on to an agar slope and I'll used it to brew with soon.
Quite why there were so few viable yeast cells in the bottle of 1845 I'm not sure.
Sierra Nevada yeast culture
The Sierra Nevada culture pictured above was actually set up a few days after the Fullers one and shows much better growth. Perhaps the 100 day maturation process that Fullers proudly declare on the bottle means the yeast is more knackered.
I used to buy slants and make starters. I gave that up a while ago. I use Safale-05 for just about everything, including English beers. I cannot tell the difference between it and WLP-001, The White Labs California Ale Yeast.
ReplyDeleteSome will say that 05 is too neutral for English styles. That is a load of *&^%$! Good amount of crystal, and hopped to style it works wonders. For me anyway. Can't stand S-04.
Never tried Safale-05, but I have used Safale-04 a lot. I don't mind it myself but I've been trying to do some lower gravity bitters recently and they have been a bit bland. So I'm tweaking the ingredients, and one of the changes I'm trying is different yeasts. As I can culture them for free I'm doing that rather than buying them.
ReplyDeleteYou should try cultureing up from a bottle of Coopers Pale Ale. Make a beer with just pale malt to 1040, hop to about 20 IBU's with one addition of pride of ringwood and use teh coopers yeast. It's simple and pretty much on the mark for a coopers clone.
ReplyDeleteI think I prefer the Sparkling Ale, that did my head in a few nights when I was in Australia. I blame the big bottles - one wasn't enough, two was too much.
ReplyDeleteI contacted my local brewery - Shepherd Neame and they happily gave me a small live culture of their yeast to use for my homebrewing. I had worked for them in the past though.
ReplyDeleteIt might be worth your while asking a few local breweries for a sample and comparing results with different yeasts.
I used to work at my local brewery and I wouldn't touch their yeast!
ReplyDeleteEd, the pale ale 'should' give you a better culture than the sparkling. You probably know better (having a microbiology background), but the higher alcohol content increases cell mortality and affords a higher rate of mutation.
ReplyDeleteTim, you're right, alcohol does stress yeast. But even so I'd be surprised if there's much difficulty culturing yeast from the sparkling ale. I remember it having quite a big sediment compared to many bottle conditoned beers so there should be plenty of viable cells.
ReplyDelete