1 week old starter

[smarks2327]

So I have yeast starter that I made for a brew last week that I never ended up brewing until today. The starter is now 9 days old. It was a one gallon starter that I made at 1.060.

What should I do with the starter? Should I decant the fermented wort off the top, put new wort on top? Can I just pitch straight into my batch? Should I make a brand new starter with new yeast?

 

[BBL_Brewer]

There's no need to start over with new yeast. Just decant the starter beer and add some more wort. If you are brewing today though, there is really not enough time to ferm out a new starter. It would be best to do this a day or two before. If you need to pitch it today, just decant and add a small amount of new wort to sort of proof the yeast and get them kicking again and then pitch the whole thing into your batch.

 

[Clementine]

1060, that is a bit thick for a starter try to keep your starter down around 1040 or below. Remember Yeast starters are to:

1) Confirm viability of the yeast
2) Improve yeast health
3) Increase Cell Count

So answering your question addressing those three areas:
- Unless your yeast got hot or froze then you know you yeast is viable after being in the fridge for only 9 days.

- Your starter was a bit thick the increased pressure on the yeast cell walls when they are in high density wort weakens the yeast rather than strengthing them.

- You can input your production date (ie when you made the starter) into a yeast cell calc like Mr Malty and it will give you a viability reading on how many cells have died since you made the starter. Basically I think you would be fine to go ahead and just pitch the slurry.

Clem

 

[smarks2327]

I have always read that high gravity beers require a higher gravity starter. Also, my starter is at room temp (65), not in the fridge...

 

[scoundrel]

I have always read that high gravity beers require a higher gravity starter. Also, my starter is at room temp (65), not in the fridge...

I have to agree with Clementine on this one. You're not trying to stress the yeast, you're trying to build them up. Making a 1.060 starter will stress them and weaken the cell wall as opposed to focusing on multiplying the yeast at a 1.040 starter and stepping them up to a higher gravity.

 

[msa8967]

So which would be worse...making a starter with the OG too low or making a starter with the OG too high? (I know making the starter with the proper OG is ideal but I am just curious about the answer to this question in regards to how the OG of the starter will affect the yeast.)

 

[BBL_Brewer]

The general consenses is to use a lower gravity wort for starters 1.030 - 1.040. However, people routinely repitch yeast from the primary yeast cake after fermenting a batch and cleary the yeast in those instances were grown in a higher gravity wort. So, can you use a higher gravity starter wort and still make good beer? Sure you can. But as mentioned above, using a lower gravity starter wort is less stessful and will result in a healthier overall yeast population.

 

[Clementine]

it depends on how you aerate.... ooooh that might bring a flame or two, so wait let me explain.

My belief is that for a given concentration and volume of wort with sufficient nutrients then the O2 is the controls the amount of yeast production as when they run out of O2 they go into alcohol production and little yeast growth goes on in this phase.

It probably sounds as if I'm going off subject, however, my point is if you have four different worts all with sufficient nutrients but differing levels of sugar and differing aeration methods then I think the following will result:

1020 shaken - Low yeast production more anaerobic fermentation good yeast health
1020 stir plate - Moderate yeast production more aerobic fermentation excellent yeast health (even better than 1020 shaken as more O2 equals fatter yeast cells)
1040 shaken - Low yeast growth almost the same as 1020 lots more anaerobic fermentation lower yeast health
1040 stir plate High yeast production good yeast health

The sugar content of the wort used in a starter is a compromise between yeast health and cell production and people smarter than I figured out 1040 is a good compromise.

Clem

 

[msa8967]

Is the general accepted recipe for yeast starters is 1 cup of dried malt extract with 1 liter of boilled water yields an OG of about 1.040? (Cannot find my copy of Palmer's Learning to Brew to check these numbers)

 

[bad67z]

Is the general accepted recipe for yeast starters is 1 cup of dried malt extract with 1 liter of boilled water yields an OG of about 1.040? (Cannot find my copy of Palmer's Learning to Brew to check these numbers)

I use the ratio from Mr Malty, 1g of dme to 10ml water.

 

[Stauffbier]

I have always read that high gravity beers require a higher gravity starter. Also, my starter is at room temp (65), not in the fridge...

I can't help but wonder what it does to the yeast to leave a starter at 65F for 9 days! Anyone in this thread have some input on that? I sometimes make a starter and then I don't get to brew when I planned, but I always put it in the fridge after 24 - 48 hours and leave it in there untill I'm ready to wake it up...

 

[smarks2327]

Thanks for all the replies! I have learned a lot. My thought is that left at room temp, some yeast has died, but certainly not all of it. I mean, I have successfully pitched on top of a yeast cake after 3 weeks in the primary and there is plenty of yeast alive and well at that point.

In hindsight, the fridge would have been the best option when I decided not to brew. I will be making 40 point starters from this point on...