yeast starter question

[bcryan]

i just saw this dude on youtube make 3 yeast starters from one vial of yeast. one he was gonna use next day for his brew day and the other two he put in the fridge for future brew days. is this a good idea? sure would save alot of money if it does work.

 

[ThePearsonFam]

There's a bunch of stuff on here about that. Some people do it that way with success. I'd rather use one vial to make a starter, pitch it and then wash the resultant yeast cake and use it in subsequent batches. That's my personal opinion though.

 

[mdgagne]

There's a bunch of stuff on here about that. Some people do it that way with success. I'd rather use one vial to make a starter, pitch it and then wash the resultant yeast cake and use it in subsequent batches. That's my personal opinion though.

How many times can you do this without mutation?

 

[Nateo]

The short answer is: Yes it would save money to make multiple starters from a single vial of yeast.

Now, the long answer: Yeast starters work best when they're not too large, or too small. If you have one vial or smack pack, you have about 100b cells. The sizes of starters that will make the most healthy growth is going to be between 1.5L and 4L, with 2L having the best yield factor. If the starter is smaller than 1.5L, you won't make hardly any new yeast. If the starter is too big, you'll mostly make beer, instead of as many new yeast as possible. So you should pitch 100b cells per 2L of starter.

I would make a 2L starter from one vial. You'll roughly double your yeast, to about 200b. So now you grew another vial's worth of yeast. You could split that in half and use one half for your beer (assuming you only need 1 vial), and save the rest, or you could save half and pitch the other half into another 2L starter.

Just dividing a single vial into 3 starters would be fine, if you follow the same 100b/2L rule. Each starter would have to be 0.66, which is pretty small, meaning that for each of those starters would make about 2/3rds of a vial. 1 vial is sometimes enough to pitch into your wort, but 2/3rds of a vial is very seldom enough yeast to do so. So you'd have to make at least one larger starter out of each of those 3 starters when you want to use it, and you might need to step the starter up again depending on the gravity. That is more hassle than I'd want.

Each time you make a starter you risk infection. Bacteria will reproduce about 100x faster than yeast, so a very small infection in your starter could become a very large infection in your beer. Sanitation is much more important when making starters than when making beer.

 

[Nateo]

How many times can you do this without mutation?

When you repitch multiple times, your risk of infection increases. With proper sanitation, this risk can be minimized, but it's always there, and even one colony of bacteria in the first pitch could ruin the 10th batch of beer you make.

Pro breweries can repitch hundreds of times, but they have amazing sanitation and wash their yeast with acid to kill all the baddies. Many pro breweries without labs only repitch a few times because it's cheaper to buy more yeast than dump a 10 barrel batch of infected beer.

So I'd say your beer will get a low-level infection that taste kinda weird or off well before the yeast mutate enough to cause the off flavors themselves.

 

[bcryan]

thanks for the solid repy. now i'm thinking if its not broke don't fix it. i make my 2L starters with one vial. beer tastes great. its only 6 bucks. save money somewhere else. thanks again

 

[Nateo]

I think if you brew frequently, with the same yeast strain, and have great sanitation, it's a good idea to either pitch multiple starters from a vial, or wash and reuse yeast.

The longer your yeast sits in the fridge, the lower the viability gets. You can probably revive them later, but it's a lot easier to work with lots of healthy yeast, instead of a few sickly yeast. I think White Labs recommends using the yeast within a couple weeks, and that seems to be a good rule-of-thumb.

I don't usually like brewing the same recipe twice, and I like using lots of different yeasts, so I seldom reuse my yeast. I've been impressed with certain dry strains from Fermentis, which drops the price of pitching new yeast at least in half, vs liquid yeast.

 

[JoeyChopps]

Another thing I have been doing is after my starter is done i usually refill the vial it came in this is a really good way of saving yeast u don't want to wash and have 5 vial of

 

[pola0502ds]

I have a question about making a yeast starter. I made one last week and poured the hot liquid I just boiled in a growler and it cracked the glass. Can someone explain to me how you go about making your starter? Do you boil it and cool it down in the pot you just boiled it in? Or do you transfer after it just got done boiling into the vessel it will ferment in and then cool it down? Whats the best way to cool something this small down?

I thought you would want to cool it down in the vessel it will ferment in that way when you transfer it while it's still hot it will kill any bacteria that is still in the vessel.

 

[stratslinger]

pola, a couple things you can do:

1) If you're going to do your starters in a growler, you definitely have to chill the starter wort before dumping it in there - the glass in a growler just won't stand up to that kind of rapid temperature change. Sanitize the growler with starsan / iodophor / whatever sanitizer you use, then transfer the chilled wort into there.

2) If you really want to do everything in one vessel, get a good erlenmyer flask - they're typically made of a special glass (borosilicate, I think) that CAN stand up to that kind of fluctuation. Boil your starter wort in the flask, put the flask into a cold water, then ice bath to chill it, pitch your yeast.

 

[badhabit]

The short answer is: Yes it would save money to make multiple starters from a single vial of yeast.

Now, the long answer: Yeast starters work best when they're not too large, or too small. If you have one vial or smack pack, you have about 100b cells. The sizes of starters that will make the most healthy growth is going to be between 1.5L and 4L, with 2L having the best yield factor. If the starter is smaller than 1.5L, you won't make hardly any new yeast. If the starter is too big, you'll mostly make beer, instead of as many new yeast as possible. So you should pitch 100b cells per 2L of starter.

I would make a 2L starter from one vial. You'll roughly double your yeast, to about 200b. So now you grew another vial's worth of yeast. You could split that in half and use one half for your beer (assuming you only need 1 vial), and save the rest, or you could save half and pitch the other half into another 2L starter.

Just dividing a single vial into 3 starters would be fine, if you follow the same 100b/2L rule. Each starter would have to be 0.66, which is pretty small, meaning that for each of those starters would make about 2/3rds of a vial. 1 vial is sometimes enough to pitch into your wort, but 2/3rds of a vial is very seldom enough yeast to do so. So you'd have to make at least one larger starter out of each of those 3 starters when you want to use it, and you might need to step the starter up again depending on the gravity. That is more hassle than I'd want.

Each time you make a starter you risk infection. Bacteria will reproduce about 100x faster than yeast, so a very small infection in your starter could become a very large infection in your beer. Sanitation is much more important when making starters than when making beer.

Where did the100b /2L rule come from? I have never heard of it before and have been making 1L starters forever I think. If it is better to step up to 2L I can do that easy.

 

[Nateo]

Where did the100b /2L rule come from? I have never heard of it before and have been making 1L starters forever I think. If it is better to step up to 2L I can do that easy.

It's from White and Zainasheff's yeast book. What I quoted was the quick and dirty, they talk about the whys a lot more in the book.

A 1L starter of about 1.030 is good if you're not sure of the viability or you're generally concerned with the yeast health. A 1L starter is still a lot better than no starter.

Otherwise, with fresh and healthy yeast, here are the (abbreviated) results from the tests they did. They started with 100b cells in each trial.

Start Volume (L), new cells created:
0.5L -> 12b new cells
0.8 > 38b
1 > 52b
1.5 > 81b
2 > 105b
4 > 176b
8 > 300b
20 > 500b

So 2L will make twice as many new cells as 1L, but larger starter volumes will make relatively less growth. So doing three 2L starters is not the same as doing one 6L starter. That's important to know when brewing big beers that call for big starters.

It's also important to remember that it's pitching-rate related. If you were to do a 2L starter, you'd end up with ~200b cells, so if you were to step up the starter, you'd want to split it into two 2L starters, or use one 4L starter, instead of just adding 2L more wort to the first starter.

 

[badhabit]

It's from White and Zainasheff's yeast book. What I quoted was the quick and dirty, they talk about the whys a lot more in the book.

A 1L starter of about 1.030 is good if you're not sure of the viability or you're generally concerned with the yeast health. A 1L starter is still a lot better than no starter.

Otherwise, with fresh and healthy yeast, here are the (abbreviated) results from the tests they did. They started with 100b cells in each trial.

Start Volume (L), new cells created:
0.5L -> 12b new cells
0.8 > 38b
1 > 52b
1.5 > 81b
2 > 105b
4 > 176b
8 > 300b
20 > 500b

So 2L will make twice as many new cells as 1L, but larger starter volumes will make relatively less growth. So doing three 2L starters is not the same as doing one 6L starter. That's important to know when brewing big beers that call for big starters.

It's also important to remember that it's pitching-rate related. If you were to do a 2L starter, you'd end up with ~200b cells, so if you were to step up the starter, you'd want to split it into two 2L starters, or use one 4L starter, instead of just adding 2L more wort to the first starter.

Thanks for the info, guess I know what is next on my reading list. Heard folks talk abuut using the 2 L starter but I only ever did so on lagers and big beers and never saw or looked for the real numbers. May be time for this old dog to learn a new trick. Thanks again.

 

[badhabit]

It's from White and Zainasheff's yeast book. What I quoted was the quick and dirty, they talk about the whys a lot more in the book.

A 1L starter of about 1.030 is good if you're not sure of the viability or you're generally concerned with the yeast health. A 1L starter is still a lot better than no starter.

Otherwise, with fresh and healthy yeast, here are the (abbreviated) results from the tests they did. They started with 100b cells in each trial.

Start Volume (L), new cells created:
0.5L -> 12b new cells
0.8 > 38b
1 > 52b
1.5 > 81b
2 > 105b
4 > 176b
8 > 300b
20 > 500b

So 2L will make twice as many new cells as 1L, but larger starter volumes will make relatively less growth. So doing three 2L starters is not the same as doing one 6L starter. That's important to know when brewing big beers that call for big starters.

It's also important to remember that it's pitching-rate related. If you were to do a 2L starter, you'd end up with ~200b cells, so if you were to step up the starter, you'd want to split it into two 2L starters, or use one 4L starter, instead of just adding 2L more wort to the first starter.

Thanks for the info, guess I know what is next on my reading list. Heard folks talk about using the 2 L starter but I only ever did so on lagers and big beers and never saw or looked for the real numbers. May be time for this old dog to learn a new trick. Thanks again.

 

[pola0502ds]

Another question, I have seen people use rubber stoppers with an air lock, foil, and foam stoppers for their starter. What your opinion on these 3 and which is preferred? Any risk in using one over the other?

 

[Nateo]

Another option for many smaller breweries is to utilize dry yeast exclusively, and pitch fresh with every batch. It cuts down on infection risk and is simple and easy, no cell counting or viability testing.

That's the route I usually take. I'm a big fan on dried yeast. With DME @ $3/lb, and a 2L starter needing roughly half a pound, that's ~$1.50 for the starter.

A packet of dry yeast is $1.75 for T-58 when I buy from Rebel brewer, a little bit more at my LHBS, or $2.45 for S-04, which is another yeast I use a lot. So it's almost the same price to pitch a pack of T-58 as to make a 2L starter, not counting the smack-pack or vial price, which is usually $6-7.

Dried yeast have a much smaller selection, but I can find a good dry yeast suitable for probably 90% of what I brew.

(Edit: If you save the last runnings of a batch and can them, then you'd have a large supply of mostly free wort for starters. That's something I'm looking into for the future to cut down my DME cost.)

 

[Nateo]

Another question, I have seen people use rubber stoppers with an air lock, foil, and foam stoppers for their starter. What your opinion on these 3 and which is preferred? Any risk in using one over the other?

White/Zainasheff recommend using a piece of foil. Bacteria doesn't have legs, so I don't see how it can get past the foil. You just need something to keep dust in the air from getting at your wort.

 

[pola0502ds]

Another yeast question, I was reading that if you want to harvest yeast from a batch of beer that is currently fermenting, you can skim the top off and harvest it that way? Question is, how the heck to you skim it off when it is in a carboy? It's almost like the only way to skim it is if you are doing a open fermentation.

 

[Nateo]

Question is, how the heck to you skim it off when it is in a carboy? It's almost like the only way to skim it is if you are doing a open fermentation.

Yep, you got it. Open fermentors are the only way to top crop. Or, take the lid off the bucket.

I've read that by top cropping you're selecting the healthiest yeast, because the sickly ones would've dropped out already, and that by top-cropping you can harvest and repitch for longer without ill-effects than by washing all the yeast. I haven't tested that personally.

 

[fergczar]

I have a recipe that calls for 2 different strains of yeast both from starters. Can I pitch both in one 5000 ML flask as single starter or is better to have a separate flask for each?

 

[Nateo]

I have a recipe that calls for 2 different strains of yeast both from starters. Can I pitch both in one 5000 ML flask as single starter or is better to have a separate flask for each?

You should be fine in one vessel. Growth curves for beer yeast are pretty consistent across strains. One strain might grow very slightly more than the other, but I doubt the population will drift much. If you start at a 50/50 mix, and viability is the same for both, you'll probably end up around 50/50 too.

 

[Fish826]

Since you guys are on the subject of starters, I'm planning on using my first starter (my second batch brewed) and I was wondering about the DME that you use in the starter. If I use the DME that comes with my kit, do I need more for my boil or will the DME I take out count towards what's needed for the recipe?

 

[stratslinger]

The extract used for your starter is definitely separate from what's in your recipe.

The stuff in your starter is simply there to make more yeast, while the stuff in your recipe is there, well, to make your beer!