Is this yeast, or DME? (pics)

[ja09]

Stupid sounding question, I know, but I recently tried harvesting yeast for the first time and here is my problem...

I was all excited because I thought my yeasties were flourishing, but then I took a gravity reading of the decanted beer, and it was 1.050!? Is the sediment in the pics below trub and not yeast?

Here's what I did:
1. Made a 500ml starter with 2 cups water, 1/2 cup extra light dme, 1/4tsp yeast nutrient
2. Pitched 1/3 can of decanted & swirled heady topper, which was very hazy
3. Used a stir plate for around 48 hours
4. Stuck it in the fridge and didn't get back to it until 5 days later (today)
5. Decanted and took a gravity reading with my hydrometer ~ 1.050

I'm in the process of stepping it up at the moment, so help is greatly appreciated!

EDIT: This is my first attempt at harvesting and my first time using a stir plate. I also don't have a ton of experience making starters.

 

[jesserizzo]

The number of cells in a packaged beer, even an unfiltered one, is going to be very low. And you used a high ABV heavily hopped beer, so the viability of the cells will also be very low. They probably weren't up to finishing that starter at all, much less in only two days.

The normal process for a starter from a vial or smack pack is at least 1L of 1.040 wort. But for this extremely stressed out small amount of yeast, something like 100ml of 1.020 would probably have been your best bet.

Too late now, though. So just keep stepping it up, and after a few steps you should be fine.

 

[ja09]

The normal process for a starter from a vial or smack pack is at least 1L of 1.040 wort. But for this extremely stressed out small amount of yeast, something like 100ml of 1.020 would probably have been your best bet.

Thanks. I thought that was a large starter, but I just followed Palmer's steps and he made it sound like I should start with a pint: http://www.howtobrew.com/section1/chapter6-7.html

So I'm guessing that is just trub in the pics? Is that amount normal? Thanks

 

[badlee]

The yeast should be a beautiful cream colour and will stand out very clearly against the trub.
Saying that, 1050 is very big for a first step starter and will have overwhelmed the yeast. I have been under te impression that you should start with a 1020-1030 wort to coax the yeasties out of hibernation.

 

[ja09]

They've come alive! I decanted down to 200ml, and brewed around an 800ml step up ~ 1.030. I wasn't expecting much, so I was happy when I saw a mini krausen after 3 days on the stir plate. On the 4th day it took off and I transferred it to a larger flask to finish.

...but since I stressed out the yeast so much on the 1st attempt, can this effect my final product? I'd assume the beer probably tastes poopy, but the yeast should be fine. I'm new at this harvesting business

 

[whitehause]

Don't know about the yeast, but nice stirplate!

Seriously though, the initial yeast were probably stressed, but if you give the offspring a nice healthy environment to grow in, you should be fine. Yeast are pretty hearty things. Remember what the yeast your harvesting have already been through....fermenting, carbonating, chilling, sitting in a bottle for weeks or months at changing temps. After all that, they still grew.

If you have more of the "donor" beer on hand, and you don't have a brew day planned soon, I'd think about doing a new harvest with a low gravity starter just for practice if nothing else.

 

[ja09]

I'd think about doing a new harvest with a low gravity starter just for practice if nothing else.

Thanks whitehause. I do plan on attempting another harvest soon now that I know some more.. maybe 50-100ml ~ 1.020 to get going. I should have done a little more research in the beginning, but I read this instead and it's just too vague: http://www.howtobrew.com/section1/chapter6-7.html

So now I guess the next question will be how do I know when I have enough yeast for a big IIPA? Is there a standard way to approximate yeast cells based on the size of the cake?

 

[whitehause]

As a general rule,( I'm sure someone else will chime in ), yeast amount is gauged by the amount of starter used to grow them. When you here one liter or two liter starter, it just means the amount of yeast that 1 liter of 1.040 wort will produce, not that you grow an entire liter of yeast. Most times I will grow a two liter starter for bigger beers. MrMalty.com has a calculator that works pretty well, though I think it's on the high side sometimes.

 

[ja09]

Thanks again whitehause. So, would this mean the original amount of cells doesn't really matter, as long as a 1L starter finishes at the correct FG?

I would think pitching a full vial vs. a half vial, say in a 2L starter, would yield more cells? Since I started my 1L starter with barely any yeast, I'd think there'd be a lot less cells than starting with a full vial. (Keep in mind I have no idea what I'm talking about)

 

[whitehause]

Remember, the yeast will stop when the fermentable sugar is gone.

Hypothetically... If 1 oz of liquid yeast takes 2 days to get to FG, they are reproducing the whole time till the sugar runs out. If 2 oz's of yeast only takes 1 day to get to FG, they are only reproducing for 1/2 the time thus producing 1/2 the cells. In theory, the amount of cells should be roughly the same assuming both starters are at the same OG (say 1.040).

Now obviously if you keep decanting off the finished wort, and add new wort, you will be building up more and more cells.

With a bottle(or can) harvest, your starting with so few cells that you need to baby them a bit till you have a healthy amount of cells. If your starting with a lot of cells, as with a vile, smack pack, or a washed cake, you can start with a full 1L at 1.040.


If I want a 2L starter begining with a bottle harvest I start small ( 250ml at 1.020) then add another 500ml of 1.030 right into the original after a day or two. Let the yeast finish that for a day or two, then turn off the plate, let the yeast settle to the bottom and decant off the finished wort.

Now you should be able to do a full 1L at 1.040. Let the yeast finish to FG, turn off the plate, chill overnight to drop the yeast, then decant again, let the yeast come back to room temp and add another 1L of 1.040 wort. Let finish,decant, and pitch your 2L starter.

Repeat for 3L,4L, however many you need, or stop at 1L if that's all it calls for.

Once you have a brew done with your harvested yeast, just wash the yeast cake (there's a sticky about this) and you won't need to do all the small steps again because you'll be starting with more yeast. Just go right to 1L,2L or more.

 

[ja09]

That makes sense. My next brew with Conan requires ~ 1.7L starter, so I was thinking of making a 2L starter and saving a small amount of the slurry for later. Not sure if I'm going to wash it or not. Might dump new one onto the yeast cake. This seems like less hassle than washing to me.