how do they sort yests in the

They do not sort them. They grow them separately in sterile environments. For them, sterile means sterile, not like use where sterile really means clean. If they ever let strains mix, they are ruined.

Ray

how do they tell them apart? microscope?

You really seem interested. I would suggest you go to the web size of several of the yeast producers. Several of them have a lot of information on there site. I have enjoyed reading it in the past.

Ray

I think they separate them by streaking plates. When they isolate a specific strain, they will use a microscope and/or streaking to make sure it remains pure.

There are some beer yeasts that are reported to be a mixture of strains, but I think all of the wine yeasts are single strains.

Andy

Yes I got that impression! I don't know if you can buy Gervin branded yeasts in the USA but Gerry Fowles, who developed these(or at least started marketing them) some years ago, lives locally to me and, although now getting on a bit, is happy to share his knowledge. He used to be a chemistry don at Reading University and then became, I think, Profesor of Oenology in the Food Sciences Department. Don't think he's on the web, though!

But it is interesting - I've made some white wines from fuit juices recently and I am fascinated by the way different yeasts work - white wine yeasts, as noticed, seem to be slower, and even there, the different strains seem to have different fermentation patterns and throw very different kinds of sediment.

Not that I'm an anorak, or have nothing else to do ut watch the bubbles, of course....

Cheers,

Andrea

Funny you mentioned that, I started an India Pale Ale with Safale yeast that was one month out of date on Sunday night. I figured it was still good but might ferment a little on the slow side since it was older and shipped around the world, I'm in the US. I have never in my life seen such a violent, healthy fermentation. It looked like I was still boiling the batch, it was something to see. I have three more packets and won't be throwing them away any time soon.

Joe

Hi Joe,

Safale SO4 is a very strong yeast. I find it difficult to harm. I use it in most of my American Pale Ales because it ferments out in a couple of days and leaves some fruity notes that I find match the citrus notes of Cascade hops. It also has pretty good alcohol tollerence (if you brew barley wines, etc.).

I usually keep a couple of packets in the fridge for emergencies too.

Andy

Aha!

I was given some nice, clean demijohns from friends and decided to test a VERY out-of-date gold label yeast. (2 years) About 3 people mentioned "tea wine" to me and I thought, well, half a packet of tea and some sugar - what have I got to lose? So I mixed the yeast with some sugar and warm water, went shopping and when I came back, yes the yeast was giving it what-for. So I made some tea wine. I have NO IDEA what it's supposed to taste like but it was made in early April and still having bubbles. I was a bit concerned so telephoned the lovely Gerry Fowles (who must be , er, quite old by now) and he was great- said " it's always worth giving it a go"...so DON'T BIN THOSE YEASTS!

PS Mulberries. We have a mulberry tree in our brilliant municipal park (it's jsut been restored, the park I mean). So I was thinking of getting together with Friends of the Earth to do a winemaking publicity thing - you know, collect the mulberries, give out some flyers saying "Count your wine miles!" and generally raise awareness that there are other ways to enjoy good wine. Does anyone have experience with mulberries? I think that here (southern UK) they ripen mid-August but I suspect they don't do it all at once. Can anyone advise? And, any views on "wine miles"?

Thank you and hope you are all well....

Andrea

PS I don't do (ie make it) beer but I am jealous of your Pale Ale, sounds great!

You bring back memories. My grandparents had 6 large mulberry trees that I climbed in and ate mulberries as a kid. They are long gone and I have no access to them or any other mulberries now sow I have never made mulberry wine. I am sure they will make good wine but they are very mild so may need adjustment than other fruit. Anyway, Jack Keller has several recipes for mulberry wine and he comments on how to adjust the basic fruit. Try