Yeast Starter and Stepping Up

[paarman]

Alright, I've done quite a bit of reading and searching.. And reading and searching.. Used a bunch of different yeast calculators and such (which are all helpful), but I need a good clear answer on a few things, that hopefully one or more of you can help me with. Here is my situation:

I am brewing a beer this Saturday (2 days away), an imperial stout with a OG of 1.091-1.095. Going off yeast calculators, I will need 430-550 billion cells for a 5.25g batch.

Yesterday evening I started a 2L starter with a strain of WLP004. Up until today, I have been manually shaking often as I don't have a stir plate.. Which I had one on order that just arrived today. So I have put the starter on that as of today.

I had planned on doing a step up by decanting this one down, and making another 3L starter. First question: do you add the 1st starter into a new container with the fresh wort, or can you add the fresh wort onto your decanted (or not) yeast in the 1st starter? Does it matter which? I do have another container to do it either way... Obviously pitching the new wort into the current decanted yeast container seems the easiest to me.

Since I have switched from manually aerating to a stir plate now, how long do you figure I need to wait until I can cold crash the 1st starter? From reading, I gather 24-36 hours on a stir plate, but now I'm not sure since it was pitched yesterday and aerated for roughly 18 hours. I also purchased a 2nd pack of yeast that arrived today, in the event that I may need it I wanted it on hand.. Being Summer time and shipping takes 2-3 days, both the original pack of yeast and the new one arrived at what I would describe "room temp".. They did not feel hot, just about what water sitting in a room would feel like. Should I be worried about the viability or life of the yeast? Will building this starter kick any potentially damaged yeast and re-grow some good ones to use if so?

So after reading all of this, would it be beneficial to pitch the new pack of yeast into the 2nd stepped starter, or just keep it on hand to do a 2nd pitch (if needed) into the carboy? Should I create a 2nd separate starter today and either put that one on the stir plate or manually aerate it and crash and decant both on brew day, and then pitch two starters? I feel I am overthinking this process but worried about underpitching.. I don't know if two separate starters is better or equal to a stepped starter. Just want some advice on the best way to proceed today, 2 days before my brew day. Thanks in advance!

 

[kh54s10]

I decant the wort from my one flask then add a new wort to that. I don't think it really matters which direction you go, but you will leave yeast behind if you add it to a new container. It will stick to the bottom and sides of the vessel.

If I were to do the intermittent shake method I would let that one go 36-48 hours or more. On a stirplate I always go 18-24 hours.

The calculator that I use is suggesting 337 billion cells. So your second stage could be a 1.25 liter addition instead of 3 liters. http://www.yeastcalculator.com/

Save the new pack unless you won't be brewing for a while. Or, if you add it to the present starter you won't need any more yeast than that. So you could skip the step up entirely.

 

[paarman]

I decant the wort from my one flask then add a new wort to that. I don't think it really matters which direction you go, but you will leave yeast behind if you add it to a new container. It will stick to the bottom and sides of the vessel.

If I were to do the intermittent shake method I would let that one go 36-48 hours or more. On a stirplate I always go 18-24 hours.

The calculator that I use is suggesting 337 billion cells. So your second stage could be a 1.25 liter addition instead of 3 liters. http://www.yeastcalculator.com/

Save the new pack unless you won't be brewing for a while. Or, if you add it to the present starter you won't need any more yeast than that. So you could skip the step up entirely.

I figure it doesn't hurt to have more yeast than I need, worst case scenario the yeast don't multiply to the estimates. It's rare to overpitch, but I would rather do that than underpitching. So I'm okay with overshooting what I need. Just don't want to get to a point where the fermentation isn't dropping to where I need to to and then I'm scrambling for more yeast/create a starter or something.

It sounds like the best thing to do is let my current starter sit on the stir plate until tomrrow. I guess the only other question I have is if I were to pitch that 2nd packet of yeast, wouldn't the wort I already have in there have had most of it's sugars eaten up by the 1st pitch? If there is plenty of sugar in there still, I'd probably rather pitch the 2nd pack now and just let it go until tomorrow night so I can cold crash and decant it Saturday morning.

Thoughts on that?

 

[paarman]

Also, one crucial piece I forgot to mention is that this yeast I pitched was manufactured 4/17/17, so it was around 50% viable when pitched. The one I got today is from March, so even less. Damn shame I can't get liquid yeast around here and ordering online from two separate places they were old strains, which doesn't help my cause haha.

 

[kh54s10]

You don't do a second step with just yeast. You make another wort and add it to the yeast cake. If you don't there is nothing to feed the yeast.

Fermentation not dropping to expected final gravity does not really have much to do with how many cells are originally pitched. They will reproduce until there are enough to ferment the beer. Hence the yeast manufacturers saying that a pack is enough to ferment a 5 gallon batch without making a starter.

More yeast than needed is OK as is a little less than needed. A big over pitch is also not good. Though it is more forgiving than an under pitch. If you went with the 3 liter second step you would have almost twice the yeast you need. Especially if using the stir plate.

You can add the second pack of yeast. Especially if you are in a time crunch. But that really defeats the purpose of making a starter. You make a starter to save money. You do this by making the starter using only one pack of yeast. The starter wort costs maybe $1. A second pack of yeast costs $7 or more.

 

[paarman]

Yeah, I get that I need to make more wort for a step up, I was just referring to your statement "Or, if you add it to the present starter you won't need any more yeast than that. So you could skip the step up entirely." I meant I wouldn't be able to just pitch the 2nd pack of yeast at this point would I? I feel like the sugars in the existing wort have already been eaten or used up so did you mean I would need to make more wort along with pitching the 2nd pack of yeast? I was just confused by what you meant.

Maybe I am misunderstanding, and forgive me if I am wrong on this-correct me if I am-but I thought the statement made by yeast manufacturers only refers to 5 gallon batches of beer that are 1.064 (about) or lower can be fermented without making a starter. On the packaging they usually suggest making a starter for anything larger than that. I guess I was under the impression that you will get a division of yeast cells up to a certain point with each starter.. So if I started with roughly 50 billion yeast cells, I should have 150 billion at the end of the first starter. And stepping up from there take those 150 billon and at least doubles that.. Is that right? I don't know why you would make a starter if it wasn't to build up to the amount of cells that you need to pitch into your brewed beer to fully ferment all of the available sugars. If you pitched say 100 billion yeast cells into a beer that tentatively called for 300 billion, you would end up with unfermented sugars, which would result in a higher final gravity, correct? Again, if I am wrong on any this, feel free to correct me.. Maybe I totally wrong on that.

I definitely care about the time saver here more than money at this point. I do get that it defeats the purpose of a starter, but in the interest of time I'm willing to eat the cost. I specifically bought the 2nd pack of yeast as a backup for this brew. Either as a 2nd pitch into the beer, or a fallback if I needed.. I didn't want a stuck fermentation and have to wait to order more yeast, or whatever else I may run into. $7 was a cheap insurance policy for me. My biggest concern was not having enough yeast cells in my initial pitch this coming Saturday. From all the reading I've been doing I thought the goal of my starter was to build up the yeast to the number of cells the recipe calls for according to the calculators, but again, maybe I am going about it all wrong.

Thanks for the replies and help, I do appreciate it.

 

[Summers]

Most ppl have a few different websites that have yeast calculators this is one of the ones I use for over building yeast starters.

https://www.brewunited.com/yeast_calculator.php

 

[TungstenBeer]

Yeah, I get that I need to make more wort for a step up, I was just referring to your statement "Or, if you add it to the present starter you won't need any more yeast than that. So you could skip the step up entirely." I meant I wouldn't be able to just pitch the 2nd pack of yeast at this point would I? I feel like the sugars in the existing wort have already been eaten or used up so did you mean I would need to make more wort along with pitching the 2nd pack of yeast? I was just confused by what you meant.

I'm coming in mid-conversation here so I apologize if I confuse. When you do a multi-step starter this is the general process. There is only one packet of yeast involved, ever.

1. Create starter wort (done)
2. Pitch yeast from manufacturer into starter wort (done - this should be close to 100B cells but for you it sounds like 50B)
3. After the starter ferments, you now have "beer" sitting atop 150B yeast cells.
4. Create more starter wort based on the calculator you're using (wort #2).
5. Decant the "beer"/spent wort from your first step starter.
6. Pour the (chilled) wort #2 onto the yeast cake.
7. Let step #2 ferment
8. Your 150B cells should now be ____B many cells (350B? 400B? whatever the calculator says)

(Repeat steps 4-8 as needed for larger starters)

Does that help at all?

 

[paarman]

That does help.. Just to see the math drawn out rather than relying on a calculator, makes more sense now (grade school math teachers rejoice!). So essentially you're getting about 3x each time you add the yeast to wort.

I ended up letting the first starter go for about 18 hours on the stir plate.. Pulled it off Friday morning.. Started a 2nd starter around 3pm on Friday.. and I pulled that one off the stir plate (earlier than I wanted) around 8am the next day, and cold crashed it. Pulled it out of the fridge about 4 hours later, decanted, and put back on the stir plate for another couple hours to acclimate.

Must have worked well, the fermentation after pitched just fired off like crazy.. I have never seen my airlock so active. Fermentation hit high krausen within 12 hours after pitching.

 

[Duffman870727]

Must have worked well, the fermentation after pitched just fired off like crazy.. I have never seen my airlock so active. Fermentation hit high krausen within 12 hours after pitching.

Sounds like you got a good, healthy amount of yeast into your beer

Fermentation not dropping to expected final gravity does not really have much to do with how many cells are originally pitched. They will reproduce until there are enough to ferment the beer. Hence the yeast manufacturers saying that a pack is enough to ferment a 5 gallon batch without making a starter.

A big over pitch is also not good. Though it is more forgiving than an under pitch.

That's not entirely accurate, needs to be defined a little more clearly. A huge under-pitch will greatly affect yeast health and performance, a slight underpitch isn't a a big deal as you've described. As the yeast colonize the wort aerobically, they use oxygen to build up their sterol reserves. Once they switch to anaerobic fermentation, if they still need to reproduce to colonize the wort, their sterols get cut in half with each cell division. 4 cell divisions are about average in a healthy ferment, any more than that and sterol reserves are greatly depleted, leading into poor cell health for the entire culture and a lackluster ferment, they get tired from all the division and cannot regulate their cell wall as well leading to excretion of excess off-flavor compounds and poor re-uptake of them.

An overpitch just results in less ester/fusel production (not good if you want that character in your beer instead of clean ferment) and overtime with re-use will deplete cell nutrient reserves (not enough food to go around to all the hungry yeasties). Not a concern if you don't re-use the yeast, so overpitch can be a strategy to produce cleaner beers.

 

[TungstenBeer]

That does help.. Just to see the math drawn out rather than relying on a calculator, makes more sense now (grade school math teachers rejoice!). So essentially you're getting about 3x each time you add the yeast to wort.

No, 3x was just an example using numbers previously used in this post. The actual calc would be much different than that.

I had the time just now to run your info through a yeast calculator at brewersfriend.com. I agree with the earlier poster who said your second step should probably have been about 1.25L rather than 3L. That said, if you used 3L you probably overpitched a little bit - but it's a big beer and that probably won't hurt. Keep an eye on it for blowoff though, wow.

 

[kh54s10]

Sounds like you got a good, healthy amount of yeast into your beer



That's not entirely accurate, needs to be defined a little more clearly. A huge under-pitch will greatly affect yeast health and performance, a slight underpitch isn't a a big deal as you've described. As the yeast colonize the wort aerobically, they use oxygen to build up their sterol reserves. Once they switch to anaerobic fermentation, if they still need to reproduce to colonize the wort, their sterols get cut in half with each cell division. 4 cell divisions are about average in a healthy ferment, any more than that and sterol reserves are greatly depleted, leading into poor cell health for the entire culture and a lackluster ferment, they get tired from all the division and cannot regulate their cell wall as well leading to excretion of excess off-flavor compounds and poor re-uptake of them.

An overpitch just results in less ester/fusel production (not good if you want that character in your beer instead of clean ferment) and overtime with re-use will deplete cell nutrient reserves (not enough food to go around to all the hungry yeasties). Not a concern if you don't re-use the yeast, so overpitch can be a strategy to produce cleaner beers.

This is true, in great detail. An underpitch so severe as you describe is unlikely in an average beer so I didn't go into such detail....

As I didn't go into detail on why an overpitch is bad. It would have to be very excessive. I just wanted to note that either underpitching or overpitching is not best practice. Unless doing it on purpose to achieve a certain character.

 

[paarman]

I was okay with overpitching as after reading much material on it, it definitely sounds like you will suffer worse off with your batch by underpitching than you would overpitching. Having to re-start or kick-start the fermentation process can lead to off flavors that will negatively affect the taste of a beer far greater than overpitching-from what I read. I'd rather have that scenario from the cost and time invested into the beer. If it was just a run of the mill cheap batch of beer, I'd not care as much and have the "well I'll change that next time". I only plan on brewing this once a year, so I'll take this trial run and make adjustments for next year if it doesn't turn out right.

I did go with a 3L starter the 2nd time, as I maybe/probably cut the first starter a bit short, I presumed I didn't get the growth I wanted had I had the time to let it sit longer. I never ended up using the 2nd pack of yeast.. I am going to take a gravity reading this weekend to see where it's at; hopefully right in the range I am hoping for as from the sounds of it I came close to-if not-overpitched.

 

[Duffman870727]

An underpitch so severe as you describe is unlikely in an average beer so I didn't go into such detail....

It can happen, happened to me actually a few months ago. I was using a Burlington ale strain (WLP 095) and harvested slurry from a batch. I fermented the batch I harvested from for 3 weeks, and used the slurry the next day after harvest. I didn't have time to make a starter, so I pitched two jars of slurry (vs. a starter made from one jar).

O.G was 1.089. After 3 weeks, gravity was still 1.046 So I pitched another jar of slurry into it. One week later it was 1.038, so I swirled the cr4p out of the carboy to rouse the yeast. Sample tasted fine, no evidence of contamination so just kept waiting.... 3 more weeks and it's 1.028, I call it there (at 8.1% abv) and bottle. No bombs or gushers so far... but it is laced with diacetyl.

Long story short, trying to work with and re-use vermont/burlington strains on a homebrew scale is tough, this strain just dies in storage (which apparently a finished beer that is just "conditioning" in the carboy cannot sustain this strain beyond 2 weeks). A starter is a must even with a new pitch from the store, and always assume low viability (large starter or step up regime).