Two Rookie Yeast Q's

[Mose]

1. So I'm doing my first starter. I did it exactly how the wiki said to do it. I read that it's likely I won't see any activity, if so, then how do I know it's working?

2. My LHBS guy gave me a few vials of yeast past the year date. I was wondering if I could do up a massive starter then wash to have a fresh bunch for storage? It's new yeast in the starter since they multiply right? And if it doesn't work then no big deal, I'm not finding out in a batch that won't go.

Any thoughts from the experts? Thanks.

 

[Clonefarmer]

1. So I'm doing my first starter. I did it exactly how the wiki said to do it. I read that it's likely I won't see any activity, if so, then how do I know it's working?

2. My LHBS guy gave me a few vials of yeast past the year date. I was wondering if I could do up a massive starter then wash to have a fresh bunch for storage? It's new yeast in the starter since they multiply right? And if it doesn't work then no big deal, I'm not finding out in a batch that won't go.

Any thoughts from the experts? Thanks.

1. You may not see any activity, but there should be a yeast cake building up on the bottom of the starter. I usually see some bubbles.

2. Past the year date is a long time and most of the yeast could have died. I would start off will a smaller size starter like 1/2 liter and step up from there.

If you want to wash the yeast I would take it from the yeast cake in the beer. That way you can see if the beer turned out ok and the yeast is worth saving.

 

[munche]

Clonefarmer, follow up noob yeast question..

When people talk about "stepping up" the yeast, what exactly does that mean? Add more wort? do you siphon out the old wort?

Thanks!

 

[Clonefarmer]

Clonefarmer, follow up noob yeast question..

When people talk about "stepping up" the yeast, what exactly does that mean? Add more wort? do you siphon out the old wort?

Thanks!

It means adding more wort. Usually you would step up no more than double the volume at a time. You can chill and decant or just add more wort. I tend to just add more wort per step.

 

[ajf]

It means adding more wort. Usually you would step up no more than double the volume at a time. You can chill and decant or just add more wort. I tend to just add more wort per step.

With all due respect, you can step up to much more than double the original volume. I quote from http://maltosefalcons.com/tech/yeast-propagation-and-maintenance-principles-and-practices

The next issue is how long will it take to generate that big starter and how do I go about doing it. Once we have a 10 ml saturated culture going it should take only a few days to reach these volumes. Close examination of Figure 3 indicates that yeast should not be diluted more than 200 times the previous volume. In otherwords 10 ml should not be stepped up to more than 2 liters. The rationale behind this is simple. During yeast propagation it is important to keep the yeast growing exponentially (Figure 3, phase III). Diluting the yeast out too far will slow down their growth and give bacteria a chance to overtake the culture. Since bacteria can grow as much as 6 times faster than yeast (the average doubling time for a bacterium is 20 minutes!), it is important to keep yeast growing rapidly. If more than 1 or 2 liters of starter are required, it is best to do more than one step-up. In most cases it is best to do a 500 ml intermediate starter and after 1-2 days step this up to as much as 1-2 gallons. In each case the yeast should reach saturation in 24-48 hours. Figure 4 outlines the two different propagation strategies.

If you are starting with very few viable yeast cells (which you will be if the yeast is over 1 year old), I would make a starter of about 250 ml or 1/2 pint (that is the first step up), and then step it up to the required size just by adding the appropriate amount of 1.040 wort. The advantage of using a small first step is that you can just add some ~1.040 - 1.050 wort to the second step and still end up with a reasonable gravity wort. If you just double the size of the starter, you will have to chill, and decant the spent wort from the first step to get a reasonable gravity for the second step, and this is not good for the continued reproduction of the yeast.

-a.

 

[Clonefarmer]

I've always doubled up on the steps and had good results. I don't decant in between though. I step up at 24-48 hours depending on activity. I can't argue with the science in ajf's post though.

 

[passedpawn]

The reason to start small is to ensure that the starter gets to >2% alchohol quickly. This protects it from infection.

Go to 2L from there.

10x steps is the general rule.

 

[Mose]

Thanks for the quick replies.

1. Had I waited to ask my question it would have answered itself. Bubbles coming through the airlock with that oh so lovely foam starting to form on the top. Things are looking up for tomorrow night's Saison.

2. I might give the step up process a try and see what happens, it was free yeast and the best way to learn is to try. I'll be washing the wheat yeast out of my brew from tonight when it's done, which will be my first try with it as well.

Thanks again.

 

[Mose]

So I did the starter like wiki said, got my bubbles in less than a day in the airlock and was feeling good about my first round.

WLP568 Belgian SaisoN

Brewed up the Saison last night, cooled and pitched. 10hrs later I checked on the progress and my airlock sounds like a jack hammer, it's firing away like there is no tomorrow. AWESOME. I just might be making a lot of starters from now on, WOW, this is a whole new world. I have the makings of a stir plate in basement, so now I just need to get it done.

Also looking forward to harvesting the yeast from this and the wheat we put up two nights ago.

Thanks to the forum for expanding my brewing yet again.

 

[kanzimonson]

The reason to start small is to ensure that the starter gets to >2% alchohol quickly. This protects it from infection.

I'm not sure I buy this. Remember, the goal of a yeast starter is to make yeast, not beer. If you continually provide your starter with oxygen (a stir plate being ideal), the yeast will remain in their growth phase. When yeast are growing, they are not producing any alcohol (or maybe a very tiny amount).

I believe the reason you start small is exactly what you and everybody else are saying - you want to provide an environment in which they'll ideally multiply by 10x. Any higher and they might have trouble outcompeting other organisms, any lower and they won't put as much effort into growth.

 

[passedpawn]

I'm not sure I buy this. Remember, the goal of a yeast starter is to make yeast, not beer. If you continually provide your starter with oxygen (a stir plate being ideal), the yeast will remain in their growth phase. When yeast are growing, they are not producing any alcohol (or maybe a very tiny amount).

I believe the reason you start small is exactly what you and everybody else are saying - you want to provide an environment in which they'll ideally multiply by 10x. Any higher and they might have trouble outcompeting other organisms, any lower and they won't put as much effort into growth.

Don't buy it then. I've grown a lot of yeast (from small frozen samples) and I think I have a good understanding of what is going on. Read MB Raine's paper (linked above) for confirmation of what I said.