Confused newbie, how to make a starter from slurry???

[pshankstar]

I would like to make my first 3 gallon BIAB IPA in the next week or two, while using some of my yeast slurry from a previous batch. The yeast was harvested on 12/6/15 and has been in the back of the fridge since then. The picture below shows a container (1 cup size), so I would say the amount of slurry in there is 3/4 cup (roughly 6oz or 0.18L).



Based on the recipe in BeerSmith the OG would come in at 1.066. Using the starter calculator I get the following results.



I'm kind of concerned with the age of the yeast slurry since it is three months old, although its been in the back of the fridge since day one. Is there another calculator to determine anything regarding a slurry's age? It sounds like I could just pitch the slurry without making a starter. Would you guys do that? I feel that I should do something to help the yeast, i.e. a start of some sort.

I would hate for me to brew my first BIAB and then have the yeast part fail me.

Thank you in advance! I'm a newbie still trying to figure out this yeast starter thing. LOL After hours of reading and what not, I feel there is so much conflicting info. I have read Gavin C's write up which is great and seems straight forward for making a starter with a new package of yeast, but not from slurry. Thank you Gavin for that info/write up!

 

[HausBrauerei_Harvey]

I would definitely make a starter. I usually just use mr malty or yeastcalculator.com not using the repitch from slurry option. I just estimate 100B cells/ml from my slurry and use their estimate for the age of the yeast to calculate the size starter needed. Hope this makes sense, FWIW I find beyond like a month mr malty just says 10% viable, the yeast calculator.com site actually does a bit more math and is better at estimating the viability of old slurry.

With all that said, even if I technically have enough cells in my old slurry, i always make a small (500ml-1L) starter before using yeast that is over 2 weeks old, then the yeast is really ready to rock. If you dont do this you'll get a long (1-2 days) lag time as the yeast 'wake up' and start rocking. I usually chill the starter and decant the starter wort, FWIW.

 

[pshankstar]

Thanks @HausBrauerei_Harvey for your quick response! I normally follow NB's instructions on making a yeast starter from a fresh pack (ok once LOL). https://www.northernbrewer.com/documentation/YeastStarter.pdf

You said you would normally make a starter in my situation. Do you typically follow the 10:1 ratio to make the starter and then just add the slurry to it and get it going? Or do you make it a little differently? Thanks again!

 

[rhys333]

If you check out the simple yeast storage procedures thread you'll find a lot of good pointers there. A safe estimate is that you lose 50% viability in 3 months, so keeping this in mind you'll have about 90B cells instead of your 180B predicted above. Since you need a starter anyway, I'd be tempted to use maybe half your old slurry and make a large enough starter to build up enough fresh cells for the remainder. If you're using the "shake" method, a 1.5L starter will do it. If you use a stirplate, then 1L should be enough.

Also 10:1 is an effective and easy way to make your starters. For example, a 1.5L starter will need 0.15kg (150g) of DME. Good luck.

 

[pshankstar]

If you check out the simple yeast storage procedures thread you'll find a lot of good pointers there. A safe estimate is that you lose 50% viability in 3 months, so keeping this in mind you'll have about 90B cells instead of your 180B predicted above. Since you need a starter anyway, I'd be tempted to use maybe half your old slurry and make a large enough starter to build up enough fresh cells for the remainder. If you're using the "shake" method, a 1.5L starter will do it. If you use a stirplate, then 1L should be enough.

Also 10:1 is an effective and easy way to make your starters. For example, a 1.5L starter will need 0.15kg (150g) of DME. Good luck.

Thanks, yes I have a stir plate to make my starter with so that should help with the cell growth.

 

[HausBrauerei_Harvey]

Thanks @HausBrauerei_Harvey for your quick response! I normally follow NB's instructions on making a yeast starter from a fresh pack (ok once LOL). https://www.northernbrewer.com/documentation/YeastStarter.pdf

You said you would normally make a starter in my situation. Do you typically follow the 10:1 ratio to make the starter and then just add the slurry to it and get it going? Or do you make it a little differently? Thanks again!

I've been using the 100g DME/Liter water rule for a while, it gets you right about 1.040 wort, which someone smarter than me determined was optimum for cell production without stressing the yeast. I guess this is right at the 10:1 ratio. I have a small scale so I just tare my flask and pour the DME right in, then add the water and go. It's pretty simple, I also started adding about a drop or two of fermcap to help with the boil overs from the flask, that stuff works great.

If my slurry is 'really' old i'll just use a little (say 100ml slurry max) then build it up over 2 or 3 steps, as I dont want a ton of dead cells throwing off my math of slurry volume. I've had great success using slurry that was even a year old using this method. I have 7 yeast strains in my garage fridge right now.

 

[pshankstar]

I've been using the 100g DME/Liter water rule for a while, it gets you right about 1.040 wort, which someone smarter than me determined was optimum for cell production without stressing the yeast. I have a small scale so I just tare my flask and pour the DME right in, then add the water and go. It's pretty simple, I also started adding about a drop or two of fermcap to help with the boil overs from the flask, that stuff works great.

Thanks for the input! What size flask do you use? I'm concerned about the the cell growth (krausen) that will form and overflow my 1L flask.

I'm wondering if I could do two small 500mL starters and combine them when pitching? Start one tonight and then place it in the fridge tomorrow and start another small one tomorrow and by Wednesday I can combine them and pitch the yeast after the wort is cooled.

 

[HausBrauerei_Harvey]

Thanks for the input! What size flask do you use? I'm concerned about the the cell growth (krausen) that will form and overflow my 1L flask.

I'm wondering if I could do two small 500mL starters and combine them when pitching? Start one tonight and then place it in the fridge tomorrow and start another small one tomorrow and by Wednesday I can combine them and pitch the yeast after the wort is cooled.

1L is a small flask! No reason you cant do it in two steps like you propose. Fermcap will also stop the krausen foam, it's great stuff. I have a 2L and a 3L flask, the 3L is a really great size for me, I brew 11G batches.

 

[emcfarden]

Try this calculator:

http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

It factors in yeast age and also calculates pitching from slurry. This along with the Simple Yeast Storage Procedures thread should put you on the right track.

 

[rhys333]

Thanks for the input! What size flask do you use? I'm concerned about the the cell growth (krausen) that will form and overflow my 1L flask.

I'm wondering if I could do two small 500mL starters and combine them when pitching? Start one tonight and then place it in the fridge tomorrow and start another small one tomorrow and by Wednesday I can combine them and pitch the yeast after the wort is cooled.

Do you have any larger glass jars, 2L or 1 gallon carboy or even a bigger pickle jar? These will work just fine, keeping in mind you'll have to make a slightly larger starter since they won't work on a stir plate.

 

[luckybeagle]

I've got kind of a dumb question. I'm doing what OP mentioned: fermenting a batch of beer using 3 month old slurry and making a starter.

My question is: does every liter of starter wort have 246 billion cells (while fresh) assuming it was seeded with viable yeast and given time to fully ferment out?

In other words, does yeast multiply to these counts and then max out at this density of x cells per ml, assuming they have everything they need for healthy reproduction?

 

[mongoose33]

I would like to make my first 3 gallon BIAB IPA in the next week or two, while using some of my yeast slurry from a previous batch. The yeast was harvested on 12/6/15 and has been in the back of the fridge since then.

''

If I read your original post correctly, that yeast is nearly FOUR years old. You're not going to just need a starter--you're going to need a time machine.

If you have any real interest in this new batch being excellent, pitching sketchy, 4-year-old yeast isn't likely to end well.

Toss it, and get some new yeast.

 

[lump42]

View attachment 651183''

If I read your original post correctly, that yeast is nearly FOUR years old. You're not going to just need a starter--you're going to need a time machine.

If you have any real interest in this new batch being excellent, pitching sketchy, 4-year-old yeast isn't likely to end well.

Toss it, and get some new yeast.

This thread should be dead too..... It was started in 2016...

 

[lump42]

I've got kind of a dumb question. I'm doing what OP mentioned: fermenting a batch of beer using 3 month old slurry and making a starter.

My question is: does every liter of starter wort have 246 billion cells (while fresh) assuming it was seeded with viable yeast and given time to fully ferment out?

In other words, does yeast multiply to these counts and then max out at this density of x cells per ml, assuming they have everything they need for healthy reproduction?

The only way to know for sure the amount concentration of cells is to count them on a hemocytometer. When the resources are exhausted will be close to the maximum amount of cells. This is also when the yeast begins to flocculate. So assuming you've roused the yeast and have everything in suspension it will be an even distribution of cells per liter.