Agar and Slants

[Shoppy]

I recently read Saccharomyces' thread on making slants and decided I want to start a yeast bank using slants. I'm new to the culturing of yeast and had a few questions about making the slants. I'm going to place an order with Cybmar based on the list in the thread. I was thinking about buying the powdered agar through them. They show nutrients and agar. Does anybody have any recommendations on which to get or what the differences are; there seems to be a big price difference between the different products. Do I need to mix nutrients in with the agar when I make the slants?

 

[theredben]

You will want to make what is called Malt Agar (MA) it is unhopped wort mixed to 1.030 and agar mixed in. Heat this mixture over medium heat until the agar is fully dissolved and activated (>65C). You do not need any nutrients. If the price of the agar scares you, you can buy it CHEAP from online wholesale food companies. This is the same source we use at work. You only need laboratory grade agar if you are doing scientific research and need a controlled, predictable product. For home use the food grade is waaay cheaper and just as good.

http://www.bulkfoods.com/agar_agar.htm

 

[JasonInBTR]

I bought the powdered agar from Cynmar just for convenience sake. Should last me forever. Here is what I do. Works well.


Yeast Slanting Process


Prepare Slants

400ml water
35g DME
2g Agar

* Boil to dissolve ingredients
* Fill slants about half full
* Fix caps backed off 1/4 turn
* Place in beakers and cover with foil
* Sterilize in pressure cooker for 15 minutes
* After cooldown tape lids and store at angle until set

Inoculate Slants
* Untape slant
* Sterilize loop and inoculate slant with source yeast
* Close and set aside while you finish all slants
* Back the caps 1/4 turn and place in a container (beaker, etc) and cover with foil
* Incubate slants for 8-10 days
* Discard any infected slants and refrigerate


Build Starter
* Take slant out of fridge and let warm to ambient
* Add ~20ml sterile wort to slant and let ferment out for 12 hours or so
* Prepare 200ml starter and pitch from slant
* Allow 12-24 hours for propagation
* Build target starter size up to 2L and step up

 

[Shoppy]

Thanks for the help. I can't wait to get started with my yeast bank.

 

[rocketman768]

You can buy agar from Japanese food stores. It comes either in powder form or in long sticks.