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RedDragon · 09-11-2010, 04:13 PM

Has anyone set up a home lab for yeast propagation, checking health, etc? If so, what tools would you need?
Thanks.

**Pappers_** · 09-11-2010, 05:07 PM

Hi Red. I harvest, wash, store and make yeast starters, but not what you are talking about. I did hear a good podcast on it, though, on Basic Brewing. If you go into their archives, I'm sure you'll find it. The guest was a homebrewer who in his professional life worked with yeast in a lab, if I remember right.

onemanlan · 09-11-2010, 05:16 PM

Work bench
A surface to work on that you can clean w/ 90-95% ethanol + Lysol(or other sanitizer).

Propagation
A stir plate + Erlenmeyer Flask(I wouldn't go bigger than 500 mL).

For Slants
Test tubes + Inoculation loop + Agar powder.

For freezer storage(-20*C)
Microfuge tubes 1.5 mL + Glyercol powder/solution + Inoclation loop

As for checking health it depends on what you define as health. There are some method to check for cell count via Serial Dilution and plating onto petri dishes. You can count the colony forming units(CFU) and extrapolate back to your original concentration of cells within reason. Also others have had success in using hemocytometers and microscopes to measure cell counts. Only problem is cell count is not a correlated directly to health of the cells either. Growth rate its actually more indicative of how healthy the cells are, but that's a whole nother story.

After typing all this up I realize this sstuff just becomes more expensive than buying yeast from a pre-existing commercial lab. All of this I typed up is from knowledge gained working in a microbiology lab that has strict policies on sensitization.

**Pappers_** · 09-11-2010, 05:19 PM

Quote:

Originally Posted by onemanlan

After typing all this up I realize this sstuff just becomes more expensive than buying yeast from a pre-existing commercial lab.

Why should this be any different than any other part of homebrewing?

onemanlan · 09-11-2010, 05:28 PM

Don't get me wrong I would love to have my own lab to do all of this. It would be so boss, but knowing the pricing of science equipment makes my head want to hurt when thinking about buying some of this stuff privately. The cost of going out to keep all your yeast strain library in working condition for use whenever you please vs making the move from bottling -> kegging is similar in my opinion. I think there are other steps to homebrewing that could benefit people more than building a lab especially when there are already 60+ strains available commercially. Also there is a lot to learn about microbiology that can create complications and headaches for the individual who believes bacteria = bugs and yeast = yeastys. Hell it can be down right discouraging at some points if you don't understand where or why your contamination may be occurring because even people who work in clean lab settings can run into that issue.

I however am a cheap bastard who wants the best of both worlds. When I buy my yeast, particularly the expensive smack packs, I like to keep them going as long as possible without breaking the bank. I wash cakes or repitch from a cake. If I need to grow up some yeast I make a DME solution in a sanitized ball mason jar + a sanitized marble(stir rod :P) then swirl that bastard around for a couple of hours off and on. Then pitch whenever it looks good. Not very scientific, but also not very expensive either.

**Pappers_** · 09-11-2010, 05:37 PM

Quote:

Originally Posted by onemanlan

I however am a cheap bastard who wants the best of both worlds.

I, too, am in the brotherhood of the cheap bastard. I basically use three yeasts currently, a witbier, california ale, and edinburgh. Buy once, harvest, wash and make a starter forever more.

logdrum · 09-13-2010, 12:27 PM

Quote:

Originally Posted by Pappers

I, too, am in the brotherhood of the cheap bastard. I basically use three yeasts currently, a witbier, california ale, and edinburgh. Buy once, harvest, wash and make a starter forever more.

I thought there were practical limits to how many generations one could squeeze out of a batch of yeast. At some point don't you risk mutation? I'm new to this type of yeast-but I have been using the same sourdough starter for the last 15 years.

-d

Wolfy · 09-13-2010, 01:23 PM

Quote:

Originally Posted by RedDragon

Has anyone set up a home lab for yeast propagation, checking health, etc? If so, what tools would you need?
Thanks.

A home yeast lab does not need to be expensive or complicated.

My 'yeast lab' an old tv/video cabinet, glass doors keep dust off my sanitized samples, the top is easily cleaned and it's easy and convenient.

From ebay:
99c pressure cooker to use for my 'autoclave'
$1 NiChrome wire for inoculation loop
99c x-acto craft knife for inoculation handle
$2 florists parafilm to seal tubes etc

Refillable butane 'hand' torch (for making Crème brûlée) from a cheapo shop.
Rubbing alcohol to sterilize.
Glass shot-glasses for holding samples and sterilizing alcohol.

Agar-agar from asian-supermarket, few cents per pack.
Starter-wort saved from previous brew, either from last runnings of mash tun or kettle dregs.
Acidified bleach for wiping down everything.

Erlenmeyer Flasks, 250ml, 500ml, 1L and 2L, directly from Lab-supply company, $4-15ea
7ml plastic test tubes ~15c each
30ml plastic vials ~30c each (both purchased in bulk and split with others)
Ziplock bags for fridge/freezer storage.
Cheap plastic tubs also for clean-storage.

I currently have about 30 yeast strains 'banked' both frozen and on slants, and within about a week I can brew with any of them, even if some are not readily/commercially available
Friends, brew-club or forum members are often open to swapping yeast samples. I often have people bring me new strains from packs they have just purchased, because they know that I'll also supply them with a slant of any yeast I have 'banked' when they need it in return.
I test for viability simply by inoculating a new slant that is then used as the first step of making a starter, it does not need to be more complicated than that.
I've made 100's of slants and so far have had to discard 1 due to an obvious infection.

It's not complicated or high-tech, but with adequate procedures and preparation, you can get very good results without having it be overly expensive.
The only thing I feel is missing is being able to freeze the yeast at -80C, the best I can do is my standard (non-frost free) -20C freezer.

Making a starter:

And making some slants:

Loop and flame source for sterilizing:

Yeast is stored in the fridge like this:

and some frozen samples (in the glass on the left) and slants (on the right):

**TXCrash** · 09-13-2010, 01:24 PM

It's been argued (and I agree) that the "mutations" that people see when continually re-using yeast are a result of bacterial infection. This is why you should always streak a petri prior to creating your new batch of slants/ your starter for glycerin storage.

I happen to have some nice Petri dishes over in the classified section for $4 each along with some other glassware...

**Pappers_** · 09-13-2010, 01:27 PM

Quote:

Originally Posted by logdrum

I thought there were practical limits to how many generations one could squeeze out of a batch of yeast. At some point don't you risk mutation? I'm new to this type of yeast-but I have been using the same sourdough starter for the last 15 years.

-d

Yes, common wisdom (it seems) is that five generations is safe. So, assuming I end up with 4 jars of yeast every I wash and harvest, that would max out at 256 batches from the original yeast - which for me, is the functional equivalent of forever.