I want to toss out there I do the oil immersion technique in YEAST now (started a couple weeks ago). I emailed white labs about it. I asked if the mineral oil used for butcher blocks was fine. And for the heck of it I inquired if 100% olive oil was ok. They never heard of using olive oil so did not recommend it. As far as the mineral oil, they just said mineral oil without being specific about 99.9% or 100%. I couldn't find any 100% mineral oil, but did find some 99.9% mineral oil for consumption (for constipation or something or other) at a rite aid or walgreens. The other .1% is vitamin E. They recommend it be sterilized before use, of course.
I am just in the stage of accumulating equipment to start making slants but I have been contemplating adding mineral oil to extend the "shelf life" of the slants. One thing I have been wondering about is sterilizing the tool (dropper, pipette, etc.) that you use to add the mineral oil. Probably over-thinking things but how do you manage this?
I am just in the stage of accumulating equipment to start making slants but I have been contemplating adding mineral oil to extend the "shelf life" of the slants. One thing I have been wondering about is sterilizing the tool (dropper, pipette, etc.) that you use to add the mineral oil. Probably over-thinking things but how do you manage this?
very glad that I came across this thread. i have been wanting to culture yeast somehow so I dont have to keep buying fresh yeast for every brew and this seems like the best method. but I do have a question. Say i make 5 slants from one fresh yeast culture. If I want healthy first generation yeast for ever brew will i have to buy fresh yeast after these slants are used up? Or once i make a starter from one of these slants can I then use that starter to inoculate 5 more slants? and essentially never run out of this yeast strain? Or would a slant made from this starter not be considered a first generation yeast?
Let's say your slant is Batch No. XXX.1, you would make fresh slants from the yeast in your second to last slant from that batch series. Just flame your loop, dip into the yeast in your slant, and rub some of that in a fresh sterile slant, repeat for as many new slants as you would like to create. Then when you're done, use the "mother" slant to make a starter for your next batch. The reason you use the second to last and not the last slant is in case one of those final two is infected. You at least have two to take a peek at and see which is more viable to act as the "mother" slant. The newly created slants are now considered Batch No. XXX.2 and have undergone very little, if any, mutation from the "mother" slant from Batch No. XXX.1.
My recipe for slant media is:
1.5% agar powder
7% DME
1% Wyeast yeast nutrient
That is by weight so if you have, say, 500mL of water you will add 7.5 grams of agar and 35 grams of DME along with 5 grams of the nutrient.
The agar powder def. works better than the stuff I got at the grocery store, which after a few months in the fridge started falling apart.
I sacrificed a plate to test the agar and it is plenty "juicy". Has a wet texture to it. I guess i'll just give it more time.
I made 12 slants yesterday and I just checked them. There is about a 1/4" of gelatinized wort at the bottom. The remainder is all liquid. Any idea what I might have done wrong? Not enough agar agar?
I only ordered 12 vials (more on the way) so I cut the recipe in half. 200ml water, 20g DME and 1.2g agar agar.
Post above you should help you
This might have been covered, but how are guys getting slants without hot break? I am using the recipe with 1.5x agar 7x DME 1x Wyeast Nutrient per 100ml water.
Also, my slants have condensation from cooling. There is enough to kind of make drops on top of the media. The media is solid but way juicy. Is this a problem?
This might have been covered, but how are guys getting slants without hot break? I am using the recipe with 1.5x agar 7x DME 1x Wyeast Nutrient per 100ml water.
Also, my slants have condensation from cooling. There is enough to kind of make drops on top of the media. The media is solid but way juicy. Is this a problem?
You're getting hot break in your agar? I got hot break when I made the wort that I used with the agar to make the slants but none that I can see when I sterilized the slants themselves.
I got that condensation as well. When I inoculated the slants the liquid ran down the sides so that yeast got below the mass of agar. The CO2 generated there pushed the agar plug up (and ultimately out) of the vial. I opened the caps of all of the vials a bit and left them at room temperature for 5 days to dry out. That seems to ahve helped and I will do it from now on as standard practice. Two "samplings" later and I have not experienced that same issue again.
Made my first batch of slants on Saturday. They set faster than I was expecting, I think I'll use less agar next time. One thing I'm concerned about though is that there is some sediment in the bottom of nearly every vial. Is this normal or did they pick up some kind of infection before they set?
I had sediment in the bottom of all of mine as well. I think it is un-dissolved yeast nutrient.
It's totally normal
Glad to hear it. I got a bit distracted and let my pressure canner sit for longer than it needed too (like a couple hours longer) when the pressure was coming down before I taped up the slants. Was worried something had creeped in there.
In section #5, when you mention dipping the paper clip into the yeast, you don't mean dip the paper clip back into the yeast each time you submerge it in the slant, right?
You just dip it in the yeast once and then into the slant 4 to 5 times.
How does it stay sterile exposed to air during the incubation period?
Are there any "cheats" for those of us without a pressure cooker? How about a large enamel pot commonly referred to as a "canner". Could I put the vial filled beakers in the canner, filled with appropriate water, and them bake the canner in the oven to get the right temperature? Or would it work on the stove top. Would the plastic lids melt? Thank you.
NaymzJaymz said:While at the homebrewing store today I noticed they had a large variety of liquid yeasts that were "past their prime" at discounted prices. Would these yeasts be good for slanting? Would the process outlined in this thread produce a strong yeast, even though it was started with a yeast that was past it's prime?
While at the homebrewing store today I noticed they had a large variety of liquid yeasts that were "past their prime" at discounted prices. Would these yeasts be good for slanting? Would the process outlined in this thread produce a strong yeast, even though it was started with a yeast that was past it's prime?
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