Yeast Slants Pt3

So I’m planning to brew a batch of Jade IPA this afternoon, and I’ve documented the process I used to step up a slant of California Ale yeast (WLP001) to make the colony large enough to pitch into a 5 gal batch of wort.  I started the step up 4 days earlier, on a Monday night, and here’s what I did:

Monday night – I removed a slant of yeast from the refrigerator and allowed it to warm up to room temperature for an hour or so.  I prepared a clean area by wiping down our flat top stove with some Starsan/water mix and set up my alcohol burner and sanitized my pipette. The purpose of the alcohol burner in this process is to create an updraft to help keep dust particles (contaminates) from falling down into the sterile wort. Before opening either the slant or wort jar, I dipped them both in a Starsan/water mix to sanitize the outside of the containers.

Adding sterile wort to the vial

In the picture above I used the sanitized pipette to take out enough sterile wort from the mason jelly jar to fill the slant
vial with the yeast culture in it to about 1/2 full (next time I think I’ll fill it 2/3 from the top). After the wort is added to the vial I resealed the mason jar, since I’ll need the remaining wort for the next step.  The yeast slant vial with the fresh wort is closed tightly and shaken for 30 seconds or so to mix the yeast culture into the fresh wort, and to oxygenate the wort a bit too. Then I loosened the lid of the vial just enough so that any pressure created by fermentation could escape and left it on the counter overnight. Slightly loosening the cap is important, since you do not want pressure building up in the vial or the yeast will not grow properly.

Tuesday Morning – when I got up on Tuesday morning the yeast were already active and starting to ferment the small amount of wort in the slant  vial.

Wort fermenting in the slant vial

Since the yeast were actively fermenting, I cleaned and sanitized the top of my freezer to prepare for step 2 in building up the yeast. I added the fermenting wort in the vial to the rest of the sterile wort in the mason jelly jar along with a sanitized stir bar, tightened the lid on the jar and shook it for a minute to aerate the wort. I then loosened the lid just enough to allow any pressure created during fermentation to escape.

Adding yeast from vial to sterile wort in jar

Finally, I put the jar on my stir plate in my fermentation fridge where I held the temp at 68. It would be OK to leave at room temp (mid 70’s), but since I plan to pitch the whole starter into my beer without cold crashing and decanting off the fermented wort, I am keeping it cooler to prevent off flavors. Here’s how it looks after I added the yeast to the jar:

Step 2 of yeast propagation

Thursday Morning – It took a bit longer for the yeast in the jelly jar to show any signs of fermenting, but after 48 hours I had definite signs that the yeast colony had multiplied and that fermentation had begun. I think the next time I try this I may reduce the amount of wort in the 8 oz jelly jar so it’s only 1/2 full instead of 2/3 full. The jump up in size from the vial to the jelly jar may have been too big of a jump, and may cause unnecessary stress on the yeast (I’m just speculating here, but 48 hours seems a bit too long to see activity).  The yeast starter is now milky in color due to the large population of yeast that has grown in the wort:

Yeast activity in step 2 of the starter

Thursday night – Ideally at this point I would have liked to let the yeast fully ferment out the wort for a day or so, and then crash cool it in the refrigerator; then I could decant off the beer and add only yeast to step 3 of the starter (EDIT – DECANTING IS NOT NECESSARY). But since I am planning to brew on Friday afternoon I need to make the final step of the starter now.

Step 3 is no different from a normal yeast starter that you would do if you bought a vial of yeast from the home brew store. I’ve decided to do a 1000 ml starter, so I added 100 grams of dry malt extract and a pinch of yeast nutrient to 1000 ml of filtered water and poured it into my 2000 ml Erlenmeyer flask. I also add a couple drops of Fermcap S to keep it from foaming all over the stove when it starts to boil, and covered the top of the flask with a piece of foil. After boiling the wort for 10 minutes I cooled it in an ice water bath to room temp. The final step is to pour the yeast and stir bar from the jelly jar into the cooled wort in the flask, shake it for a minute to oxygenate it, and put it on the stir plate in the fermentation fridge and keep the temp set at 68.

Starter after adding yeast and shaking to oxygenate

Friday morning – I’ve already got activity in the flask – the yeast are happily eating all the sugars in the final yeast starter.

Final yeast starter with fermentation underway

I’ll be brewing this afternoon, and the final test will be to see how well the yeast perform in the 5 gal batch of beer, and how the final beer tastes. I’ll update this post in about 2 weeks with results!

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Posted on August 12, 2011, in Yeast Propagation. Bookmark the permalink. Leave a comment.

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