Yeast starter question

[gjsumm]

Hello I started a yeast starter with a 1332 Northwest Wyeast after I smacked the pack and waited 3 to 4 hours the pack expanded but not as much as my other Yeast packs I have smacked get.The date is 10 Nov 10 on the pack.It has been in a frig since Jan.
My question is the pack to old and in my starter how will I know my yeast is good in the starter. I am using a 6 ounce wort which has been chiller in a 1000 ml flask. I am using a foam starter. This is my first starter.
Thanks

 

[JonK331]

you want to let the starter ferment at normal fermentation temps, not in the fridge. Not sure what a "foam" starter or a 6 ounce wort are. Do you mean 6 oz of dme in 1 litre????

 

[BigTerp]

Somebodys been into the homebrew!!!

 

[WHYB]

More than likely your yeast has very low viability. (10%) If your going through the trouble of making a starter than my suggestion would be to dump what you have and start with a more recent pack of yeast. Anything over 2 months is pushing it... using a different yeast that is fresh is better than the right yeast that is old.

 

[gjsumm]

Geez I just proof read my question and it sounds like I drank the starter , But yes I used 6 oz of DME to a 1000 ml of water.also I have a foam stopper, WHYB yes I am thinking of just ordering a new pack, I do have a dry yeast I can use but I like the Wyeast better.

 

[emjay]

More than likely your yeast is has very low viability. (10%) If your going through the trouble of making a starter than my suggestion would be to dump what you have and start with a more recent pack of yeast. Anything over 2 months is pushing it... uUsing a different yeast that is fresh is better the right yeast that is old.

It's going to be well below 10%. The calculators I'm aware of don't calculate below 10%, but you will get that kind of low viability in about 4 months - and this is older than 9 months.

Obviously, there's SOME viable yeast if the pack swelled. But it will be very small.

If I didn't want to just buy new yeast, I would start it off in a 100ml starter - that's about 10g (or 1/3oz) of DME. Then I would step it up 10-fold, which is a 1L starter with 100g (or 3.5oz) of DME. That should bring the viability to about 50billion cells, or basically equivalent to a 50% viable smack pack. I have a stirplate though, and this is all assuming the use of one. The 50B cell count is a very rough estimate, but with a basic idea of the very low initial viability (I'd say under 1%) and the two step-ups (multiple step ups of appropriate sizes actually produce increasingly consistent cell counts), it should be a good enough estimate.

From that point, you can use MrMalty or another calculator to figure out what to do with 50% based on the gravity of the wort you're ultimately pitching into.

 

[WHYB]

Drank the starter... nice...

Sorry to say but, if you want to brew soon and your only options are the dry yeast vs the starter you have, then I would go with the dry...

 

[Clementine]

More than likely your yeast has very low viability. (10%) If your going through the trouble of making a starter than my suggestion would be to dump what you have and start with a more recent pack of yeast. Anything over 2 months is pushing it... using a different yeast that is fresh is better than the right yeast that is old.

Save the yeast! Yeast have rights too!

The worst case scenario is you will have to do a two stage starter.

To communicate more easily with other forum members it helps to speak in terms we use to describe starters. Usually you will say I'm using 1000ml or 1qt or 1L starter referring to the amount of liquid not the size of the flask/container. If you want to be specific you can spec the gravity of the wort you are using ie 1040 or 1 cup per 1000ml water etc. That might be why people are confused with your question.

What you might want to do to guarantee you have enough yeast is do a 500ml starter, then crash cool (aka fridge for two days), decant and then do a 1000ml starter and pitch when it is at high krausen (about 12- 24hrs).

 

[WHYB]

You mentioned this was your first starter... keep in mind each time you do a starter you run the risk of contamination and if you don't have a stir plate you could be looking at 3 step ups to get to 100 b. (Your 1L flask limits your growth potential)

 

[gjsumm]

Thanks for the great advise ,I looked this morning and my starter has the cake on the bottom.
I will order some more, but I am going to play with this one.I will test the gravity when I get home from work tonight ,what should the gravity run about?
I love this strain in other kits.This is my first step to go all grain.

 

[WHYB]

Are you asking about the gravity of the starter? I normally don't check this, if you keep the temp up (75-90) you should see everything completed with in 36 hours.

The final gravity will depend on quite a few things. Most notably, yeast health, the OG of your starter and the attenuation potential of your yeast strain. I estimate your OG to be around 1.070ish, multiply this by the attenuation rate 69% for your strain. Your looking at around 1.022ish (24-36hour mark) if all goes according to plan.

Let us know what you come up with ...

 

[Clementine]

When I fridge and decant my starters, I usually will check the gravity, taste it, smell it, if I had a microscope I would probably try to use it too!.

I figure any information I can gain about how the starter is performing will help me make a better beer from it. An example of this, is if your 1.040 OG starter has a FG of 1.002 then you can bet you have an infection as your SG reading should not be that low (for normal yeast). Have not had that happen yet, cross fingers touch wood.

Clem

 

[gjsumm]

Day 2 my yeast starter sure has a lot of activity going on.It is bubbling and churning pretty good and a large cake on the bottom of the flask.I will check it tonight then I guess I will put in frig, decant and maybe run one more starter off this one with the cake.Does that sound correct? I am being very careful with sanitizing everything.Thanks again for your help.

 

[emjay]

Day 2 my yeast starter sure has a lot of activity going on.It is bubbling and churning pretty good and a large cake on the bottom of the flask.I will check it tonight then I guess I will put in frig, decant and maybe run one more starter off this one with the cake.Does that sound correct? I am being very careful with sanitizing everything.Thanks again for your help.

What beer are you going to make with the starter? What is the expected OG of that beer?

I'd like to give you the best advice possible, but I'm just not sure of all the details. Have you only put the yeast into this single starter, or have you already stepped it up into a second batch of starter wort?

Also, the starter you have right now - 6.5oz DME for a 1000ml starter - is using waaay too much DME, by about double. Not only are you wasting money, but the higher gravity (and subsequent alcohol content) stresses the yeast.

 

[WHYB]

Yes that is correct gjsumm. You can also go lower on starter gravity for the next step up. 4oz for 1L is plenty. I'd estimate you will have around 25 B cells at the finish of this first starter. 70 B cells at the finish of your second starter.

 

[emjay]

Yes that is correct gjsumm. You can also go lower on starter gravity for the next step up. 4oz for 1L is plenty. I'd estimate you will have around 25 B cells at the finish of this first starter. 70 B cells at the finish of your second starter.

No way he has 25B cells at this point, even if he used a stirplate.

 

[WHYB]

You mentioned the pack did swell just not as much as normal. This would indicated that you do have some active yeast. I'm guessing your starting with 5B cells which is a good middle point, half way between the 10% and 1% viability that some estimators are predicting. The inoculation rate you've listed for the 1st starter gets you a growth factor of about 5.25. The nice thing here is even if the viability was lower (than 5B) this would in turn decreases the inoculation rate which then increase your growth factor, that is why I'd give out a guess of 25B. In the end it's only a "guess"

 

[gjsumm]

I bought a used stir plate off ebay do you leave the starter on it and turning all the time?

 

[WHYB]

Yes, do you have a stir bar?

 

[Clementine]

Things to remember yeast cell growth is determined by O2 and nutrient content of the wort they are in, this is why stir plates work so well they drive out the C02 move the yeast around to all the sugar that is in the wort (keep them in suspension) and provide access to lots of O2 hence why you see a massive increase using a stir plate. So if you pitch a small number of yeast into a really large starter you will see an increased growth rate but not necessarily what you would think. You could get the same growth from a smaller starter and lots of O2. As once the O2 is gone the yeast switch to alcohol production just like when pitched into a real wort. So just because you are seeing bubbles does not indicate increase in cell numbers or health.

To go even further when plating yeast and using a single colony of yeast to grow a starter you are infact growing billions of cells from a single cell and this can be done in a matter of days

plate yeast -> 48hrs single cell grows to a colony

10ml starter wort, pitch single colony only containing thousand or so cells aeration shaken -> 48hrs results 20 MYC/ml = 200MYC

100ml starter wort pitch 10ml wort aeration shaken 60 MYC/ml -> 48hrs results 6BYC

500ml starter wort pitch 100ml starter aeration O2 and stired 180-360MYC/ml -> 48hrs results 90BYC

1000ml Starter on stir plate 180-360MYC/ml -> 48hrs results 180BYC

(Info taken from Maltosefalcon website on yeast propagation & maintenance)

So my point is turning 5 BYC into 25 BYC using a stir plate is low balling it, step it up to a second starter on your stir plate and you will be fine.

Clem

 

[WHYB]

Why do some people insist on detailing scenarios that don't pertain to someone’s particular question?

 

[Clementine]

WHYB, I detailed a scenario as emjay doubted your numbers of 25 BYC and I believed your numbers to be correct and just gave an example of numbers I was working from on a recent plating culture I grew.

I also talked about O2 levels as the OP was asking about gravity and final gravity of your starter has little to do with cell numbers.

Sorry you missed my point, perhaps it was a long winded way of saying it.

Clem

 

[gjsumm]

Yes, do you have a stir bar?

Yep sure do on the stir bars ,so I guess I need to put this one in the frig decant then make my second batch but this time use the stir plate all the time.

 

[WHYB]

Do you plan on brewing with this yeast or are you experimenting? Both?

 

[gjsumm]

What beer are you going to make with the starter? What is the expected OG of that beer?

I'd like to give you the best advice possible, but I'm just not sure of all the details. Have you only put the yeast into this single starter, or have you already stepped it up into a second batch of starter wort?

Also, the starter you have right now - 6.5oz DME for a 1000ml starter - is using waaay too much DME, by about double. Not only are you wasting money, but the higher gravity (and subsequent alcohol content) stresses the yeast.

Well the OG suppose to be 1.052 on my Brown ale kit.About the DME amount I used what I saw on a you tube video.

 

[gjsumm]

Both on the yeast ,but mainly experiment to see what I can accomplish with it.Next batch calls for the same yeast.

 

[emjay]

Well the OG suppose to be 1.052 on my Brown ale kit.About the DME amount I used what I saw on a you tube video.

All you have is a 1L flask? And I'm guessing you don't have a stirplate?

 

[gjsumm]

All you have is a 1L flask? And I'm guessing you don't have a stirplate?

Yes I have a stir plate and only a 1 L flask I also have a stir bar.

 

[WHYB]

The stir plate should really help things along... if you did a full 1 L on the next step you'd probably be over 100B, but if you wanted to brew a 1.052 with this yeast you'd still need another step up to get to approx 190B. Have you decanted yet?

 

[emjay]

Yes I have a stir plate and only a 1 L flask I also have a stir bar.

Okay, well having a stir plate is good. If you had no stir plate and only a 1L flask, building up a proper starter would be totally unrealistic.

With a stirplate, it will still take a bit of time, but 2 more steps happens to create an almost perfect amount of yeast, if you're up to it.

Basically, you have to chill your current starter in the fridge so that the yeast crashes to the bottom. Pour out all the liquid on top, and use that yeast to pitch into another 1L starter (make sure you don't boil the yeast!)

Then make sure this new starter ferments completely, stick it in the fridge, and basically repeat so that you make another 1L starter with THAT yeast. But this one, you pitch into your batch when it's at the peak of fermentation (24-48 hours after pitching the yeast into it).

Essentially, you should build up that yeast with 2 more starters. Both the starters should be 1L, and made with 3.5oz of DME.