Yeast Farming

[pint of lager]

BJCP Education Director Posted Today, 09:50 AM
When I culture yeast, I plate it on Wort-agar plates, pick a single colony and grow it up.

From my understanding, it is better to pick a few colonies and use them rather than just one.

This means you have a spread of yeast, not just from one genetic strain.

You pick colonies based on size, "not too big, not too small."

 

[chiller]

Ive been working in a lab with yeast for about 10 years now. The problem with yeast farming is that you must insure the quality and health of the yeast. The most know way to do this is to 'acid wash' your yeast. Basically, by washing your yeast in acidulated water you kill a lot of the bacteria. This is because the cell wall of the bacteria are different from yeast however the problem is that is reduces the viability of healthy yeast. The new method is to use Sodium Chlorite (NOT bleach, thats Sodium HYPOchlorite). Basically, it oxydizes the crap out of the bactera making them rupture.

CHLORINE DIOXIDE is the chemical you are talking about not the typo you mention above.

As for availability in Australia I'm not sure.

For homebrew culturing on petri dished Pint of Larger's erring on the side of caution makes a lot of sense.

Steve

 

[nonicman]

This link provides a bit of background on Chlorine Dioxide.

National Pollutant Inventory Database

Chlorine dioxide gas is flammable, and is violently explosive in air at concentrations over 10%. It can be ignited by almost any form of energy, including sunlight, heat, or sparks.
Chlorine dioxide is strongly oxidising, and reacts violently with organic chemicals and can be detonated by sunlight, heat, or contact with mercury or carbon monoxide.

quote from the above link

Seems a bit dangerous for home use (unless you can get a stabilised version), but it is widely used and is approved for use in food preperation, paper, it's used as a water treatment and is found in alternative medicines :blink:. From digging through Google it seems that chlorine dioxide is manufactured in situ due to the above explosive properties.

I'm not a chemist but was wondering if hydrogen peroxide (diluted) could be used instead for washing yeast? It seems to have similair properties to chlorine dioxide, but readily available in a stable form.

 

[BJCP Education Director]

Chiller,

No I was quite right. Sodium Chlorite is very safe and easy to use. If you activate it by adding it to acidulated water it will produce chlorine dioxide gas in the water. At the working concentrations 20-50ppm it does wonders AND its extremely safe. Most big breweries use it as a non-rinse sanitizer.

As for the yeast colonie choosing, you want one single strain with one single genetic background. Thats why each yeast has different characteristics. If you mix strains then you loose this. It took Emil Hansen a very long time at Carlsberg to isolate the first pure strain of lager yeast.

 

[chiller]

Chiller,

No I was quite right. Sodium Chlorite is very safe and easy to use. If you activate it by adding it to acidulated water it will produce chlorine dioxide gas in the water. At the working concentrations 20-50ppm it does wonders AND its extremely safe. Most big breweries use it as a non-rinse sanitizer.

As for the yeast colonie choosing, you want one single strain with one single genetic background. Thats why each yeast has different characteristics. If you mix strains then you loose this. It took Emil Hansen a very long time at Carlsberg to isolate the first pure strain of lager yeast.

[post="50773"][/post]​

Ok,

In your post you refer to one chemical and in the link a different chemical is mentioned.

I don't accept your "knowledge" because you post as BJCP whatever.

If you are going to post please ensure you are not posting confusing material.

It is very easy on the net to claim contact with anyone without proof as to your bonifides.

You may be who you claim to be but then again .... maybe not. On rec.crafts.brewing there is a troll called Mr. Giggles, maybe you know him?

Any of the information you cite is readily transcribable off the net. Many of the brewers on this forum have an extensive knowledge of short and long term storage of yeast based on practical experience. A few go to the trouble of washing yeast with acid but that is not a common practise for homebrewing here in Australia. In a conversation I had with Dave Logsdon last year in the presence of others on this list both the pros and cons were discussed.

Steve.

 

[BJCP Education Director]

The ONLY reason I started reposting to this site is b/c I know Australia is trying hard to work with the BJCP, as is South Africa, to standardize the home brew judging competitions. You guys have a lot of good brewers with good knowledge and information.

CHiller is absolutely correct. I could be Mr. Giggles. I frankly dont really have the time to be posting as I do. Ill check back from time to time.

If you need anything or have any input you can contact me directly at: [email protected]

Name's Kristen England

 

[nonicman]

Chiller, I've have a look around for the conversation with Dave Logsdon, I'm guessing this was a face to face conversation?
Since moving to QLD I've found that good yeast is hard to get (LHBS don't stock it), not having a car, getting to Brisbane is not a viable option ($50 plus for public transport). I ordered some yeast via a website (will remain unnamed) and was sent yeast that expired 2 months ago, it took five days for the smack pack to come alive (posties leaving the package outside during doesn't help). Not real impressed with being sent an expired product with no warning. So getting everything out of what is available makes sense.
For the moment I will stick to the farming advice I have picked up from yourself and others. I don't like the sound of acid washing or using CD.

BCJP, your post needs a bit more detail, as it was a little confusing for noobs like myself.

 

[chiller]

Chiller, I've have a look around for the conversation with Dave Logsdon, I'm guessing this was a face to face conversation?

[post="50799"][/post]​

Yes the conversation was at a function organised by Grumpys last years. Dave Logsdon was in Australia and we were fortunate enough to have the benifit of the direct access to his knowledge. From memory Jayse, MAH, TDH and others were there. It was a very informative night.

Steve

 

[Trough Lolly]

As was your original post, Steve - thanks...

TL

 

[Hoops]

I have been thinking of making some starters or yeast farming with an Oktoberfest yeast.
I have been thinking though, since it is several yeasts would the yeast mix change in ratio and not be true to form next time? ie survival of the fittest yeast. So if conditions were better for once yeast than another would you get an imbalance?

Hoops

 

[Jovial_Monk]

Yes

 

[fergi]

what an excellent question hoops,i myself have thought about why yeast deteriates over succesive culturing and that was one of the reasons i had in my head ,but thought in the end probably not worth asking incase it was a bumb question, glad you put it up
fergi

 

[pint of lager]

Fergi, you may have missed a bit of info to understand what is being posted.

Some of the supplied yeast tubes are actually a mix of strains, rather than an individual strain. When these are recultured in starters, it is unknown which strain will dominate after two or three step ups.

This is even more important if you are culturing out of a petri dish when individual colonies are being selected. It is impossible to know which strain you are selecting, and for this reason any yeast farmer avoids mixes like the plague.

When continually reusing yeast slurry from bottles and stepping it up for starters, any infection will show through. The yeast doesn't "deteriorate", it is the risk of infection that increases.

When continually restreaking and reculturing yeast, there is a gradual "drift" in the population due to mutations of the yeast. Once again, the yeast doesn't deteriorate as such, it just slowly changes character. Unless you select only one colony that has mutated, then it will show marked change, rather than a drift. This is why when I culture, I select a number of colonies rather than just one colony from a plate.

 

[jgriffin]

I thought that i would post my current Yeast starter method. I used to do the stubbie-starters, however my santitation must have not been up to scratch. After 6 months or so in the fridge, they started to show signs of infection.

So i decided to make the leap into plating. I've got most of the gear (thanks hoops!) but haven't managed to get a pressure cooker yet, or had the time to be honest (don't ever start a company, your brew time goes to nothing).

Anyway, i have adopted a hybrid system atm that appears to be working very well for me.

First step is to boil 200ml of wort in a 500ml Ernelnmyer flask on the stove for 15 mins with the foil "lid" on the flask for the duration. I then let the flask cool a fair bit, before shoving it in an ice bath, removing and allowing to dry.

I then take a disposible syring (5 for $1) and a tube of yeast. Shake the tube to suspend the yeast, and suck up aroun 0.5ml of yeast into the syringe. Then i carefully squirt this into the wort, and safely dispose of the syringe.

Obviosuly i then step up to a large amount of wort as per normal.

With this method, i'm only storing the original (hopefully infection free) yeast sample - so no infections from poor sanitation or "floaties" that will cause problems 6 months later. It's not as scientific as plating, but loads easier i imagine, and heaps "cleaner" than boiling the wort in a saucepan and transfering to another bottle.

 

[Darren]

I thought that i would post my current Yeast starter method. I used to do the stubbie-starters, however my santitation must have not been up to scratch. After 6 months or so in the fridge, they started to show signs of infection.



Anyway, i have adopted a hybrid system atm that appears to be working very well for me.

First step is to boil 200ml of wort in a 500ml Ernelnmyer flask on the stove for 15 mins with the foil "lid" on the flask for the duration. I then let the flask cool a fair bit, before shoving it in an ice bath, removing and allowing to dry.

[post="72684"][/post]​

JG,
Putting the flask in the microwave will probably save you 5 or more minutes. Just adjust the power setting if you are getting boil-overs. Remember you need to biol for 10 minutes to get sanitation

I then take a disposible syring (5 for $1) and a tube of yeast. Shake the tube to suspend the yeast, and suck up aroun 0.5ml of yeast into the syringe. Then i carefully squirt this into the wort, and safely dispose of the syringe.

Obviosuly i then step up to a large amount of wort as per normal.

With this method, i'm only storing the original (hopefully infection free) yeast sample - so no infections from poor sanitation or "floaties" that will cause problems 6 months later. It's not as scientific as plating, but loads easier i imagine, and heaps "cleaner" than boiling the wort in a saucepan and transfering to another bottle.

[post="72684"][/post]​

Sounds like the way to go

 

[Mr Bond]

Found this recently and it filled in a few gaps for me,Thought i would tack it onto this thread as it may be helpful to newbies or,stir up some debate/conjecture on an interesting topic.

http://www.maltosefalcons.com/tech/MB_Rain...t_Culturing.php

 

[Plastic Man]

Some more good links for info on plating, yeast, other microbes, etc.

1/ looks like a guys uni assignment. Great info especially if you were actually setting up a micro:

Paul Smith (2001) Article / Assignment on controlling microbes in a brewery. Published on Brew Monkey Web Site. http://www.brew-monkey.com/articles/MBS21.doc

2/ looks like a lecturers notes. A good summary and some good info.

Stephen T. Abedon (1998) Microbiology Lecture. http://www.mansfield.ohio-state.edu/~sabedon/biol4035.htm

3/ Download the brewers laboratory handbook. Some good no nonsense info.

Brewing Science Institute (2003) Brewers Laboratory Handbook PDF Download www.brewingscience.com

Some good reading in here !!!

 

[Wreck]

I was digging through my fridge and found a first generation yeast that is over a year old now. I've also got a 3rd generation of the same yeast, that would only be a few months old.

Which is better to use? The older, closer to the original yeast, or the fresher version?

Thanks,
Wreck.

 

[pint of lager]

Tough call.

Usually you go for the sample closer to the original source, but yours is old. It will kick up, start with a small volume starter around 100ml and when it is working step up.

The fresher more recent sample will kick up quicker but with a greater risk of some sort of contamination.

Depends on your level of cleanliness and how good you are at picking problems in your starters.

I don't think I could recommend one over the other. Maybe you could start both of them up and try them both.

It may be time to get a fresh sample.

 

[pint of lager]

Brissybrewer took the time to write up his method of splitting commercial liquid yeasts in the following topic. Frozen smackpack topic.

How to Split a white labs tube

EQUIPMENT
Test Tubes 18mm plastic with screw cap lid (autoclaveable)
Distilled Water (I use demineralised water sold for Irons)
1 x Syringe Reusable Soda Lime Glass (autoclaveable)
1 x 13 Gauge reusable stainless steel needle (largest gauge as yeast slurry is think and hard to suck up)

Miscellaneous equipment
A Pressure Cooker (ensure you buy a high pressure cooker that holds 15psi, some pressure cookers do not achieve this)
Test Tube Rack (one that fits inside your pressure cooker)
1 spray bottle full of idophor
1 flame source (I use one of those portable butane burners)

PROCEDURE

Preparation:
1. Fill each test tube with 5ml of distilled water.
2. Cap Test Tubes and place upright in autoclave
3. Autoclave tubes and syringe and needle at 15psi for 25 minutes (ensure that you time it from when the steam starts to blow off at 15psi pressure relief setting, allow air to vent for a couple minutes then reduce heat and ensure slow escape from the pressure valve at 15psi for the remainder of the time)
4. Allow Tubes to cool inside the autoclave (if you remove the tubes and crash cool them and they will suck in dirty air and be more susceptible to infection)

Now you have your tubes read for use, if you have prepared more tubes then you care to use at once, sanitise your hands, put gloves on and sanitise your gloves then screw tube caps tight and place in the refrigerator for later use.

Sanitise
1. Sanitise Everything by wiping down all your benches equipment and anything in the area with idophor I suggest for surface sanitation to use a 50ppm concentration. After wiping everything down use a spray bottle containing idophor to spray all surfaces again including your arms and hands. At this point wipe your spray bottle down.
2. Put a face mask on if you have one surgical grade 2 or better preferably.
3. Turn on your flame (work close to your flame)
4. Put rubber gloves on, unless youre a double gloving spray your gloves with idophor as well.
5. Spray your test tubes and rack with idophor

Sterile Transfer Technique
1 Loosen caps on all test tubes so they are just sitting there.
2 Loosen cap on your white labs vial
3 Remove Syringe and Needle for foil wrap used in Autoclave
4 With the needle in one hand and the white labs vial on your bench-top take a deep breath and do the following whilst working close to your flame.
5 Flame needle just before dipping into white labs vial, the wort on top will cool the needle before you draw the slurry which has settled on the bottom, it will be difficult to draw up.
6 With one hand remove cap from vial draw up 5ml of slurry
7 Replace cap on white labs vial
8 Lift each test tube cap with one hand and inject 0.5 to 1ml of slurry in each tube and loosely replace cap
9 If you need to do more tubes repeat steps 5 to 8 otherwise put down syringe.
10 Lightly spray all loose caps and tubes from the top with idophor.
11 Spray gloves again
12 Remove one test tube at a time and screw cap up tightly and give a mild shake side to side.
13 Label and Place in fridge for later use

Bringing your stored yeast back to life

Sterile wort preparation
1. You need to prepare some wort 1030 to 1040 (unhoped)), try and achieve a good hot break because you will get more hot break in the autoclave again.
2. Insert 5mls into a number of test tubes
3. Autoclave for 25min
4. Allow to cool naturally and then tightly cap
5. Store in fridge for another day

The Yeast Awakening.
1. Take one test tube of sterile wort, and one test tube of yeast under distilled water.
2. Shake your test tube of yeast and distilled
3. Follow the sanitise steps above.
4. Over your flame pore your distilled water and yeast solution into your wort tube.
5. Cap shake and wait a day or two before it come alive it will release C02 when uncapped, warning beware of mini volcanos.