Wednesday, October 8, 2008

Been Caught Stealing...

"I've been caught stealing; 
once when I was 5... 
I enjoy stealing. 
It's just as simple as that.
Well, it's just a simple fact. 
When I want something,
I don't want to pay for it." 
- Jane's Addiction

If there has been one fact that took the longest to get though my tough head in brewing it would be that yeast, more than anything, contributes the largest part of the flavor profile of a finished beer.

Well, it's just a simple fact.

You can take some pale DME (or two row if you're into the all-grain thing) and you can make 6 different beers simply by your choice of yeast. A Belgian will make a lemon, sharp, fizzy beer, an American ale yeast like Safale US-o5 will make a clean crisp ale with some light fruity esters, or a heff yeast will again produce something totally different with banana esters and a hazy profile. All from changing one element. The Yeast.

So when it comes to enjoying the fruits of another breweries labor, I first go to the yeast. In this example, we are culturing yeast from a local brewery that in my opinion has some of the greatest ale yeast flavors I've found, Real Ale Brewing Company out of Blanco, TX. In this example their "Full Moon Rye Pale Ale".

Generally I've found good results, if I'm unsure the amount of yeast sediment or the viability of the dregs in the bottle, by creating a 10ml mini-starter. I then take the beer, pour off the good stuff in a glass to enjoy, and take the last little bit of the dregs swirl them around and then pour 5ml into the test tube to get a total of about 15ml of a mini-starter.

Wait that out for a couple of days to concentrate and wake up the dormant yeast (swirl or gently rock tube from time to time if you are the touchy feely type). This is also is a good time to prepare a few plates for the next step (See previous post on Beer Agar & Broth).  

Then with a very clean work area, working around a flame, and as always flame openings of containers when pouring (*You are flaming right!? Right?!?), open the tube with the broth and captured yeast and pour all but the very bottom sediment into another container (like a 50ml flask you see in the pic). Then get your inoculating loop red hot and get a film of the slurry/ sediment on the loop.

Next carefully half open the plate and streak the plate in four sections, rotating the plate counter clockwise (see image left). With each new section try to overlap with the streaks you did prior. Then close the lid, and place plate upside down in a clean place undisturbed.

The concept is that the streak in 1 is going to be the most concentrated (with yeast and other unmentionables), so we are trying to reduce the amount of cells with each new section in order to attain a single yeast cell to start a colony when we get to section 4.

After 24-48 hours you should see some activity. Yeast colonies will look like white puffy globes. What those look like and what you can do with them will come in a later post...

* - I haven't really covered sanitation or "Flaming" at this point, but I intend to at some point. I figure if you get this far, you should have a basic knowledge of sanitizing your equipment or at least Google some of these concepts before continuing.

1 comment:

Anonymous said...

Dood, awesome blog! I'm actually a molecular biologist and I have to say you've got quite the home laboratory going on there. And your sterile technique is impeccable. Impressive! Cheers, Pete