Saving a little dry yeast, making a starter

[jonpecan]

I have a proposition, and would appreciate the feedback.

I'll start with the idea, and then give the longer thought process.

Step 1: Brew 5 gallons of delicious beer
Step 2: Open a reliable dry yeast packet, pitch MOST of the yeast (maybe 3/4)
Step 3: Controversially save the remaining dry yeast in the refrigerator (various methods have been suggested on other threads)
Step 4: Perhaps months later, make a starter from the saved yeast remaining from the dry pack
Step 5: hours/days later, brew 5 gallons of delicious beer
Step 6: Pitch the yeast starter

Saving portions of a dry yeast pack - I've read numerous threads. Most folks say that you can't save the yeast for very long. Some say they have saved the dry yeast for months after opening. Many say it's not worth losing the peace of mind. But many say it is not a problem.

One saving grace of this theory, is that observing the progress of the starter might be enough to convince you that the yeast is sufficient and healthy. Admittedly, I seldom have used starters.

I have used yeast cakes in the past, but some of the beers I make I suspect are liable to leave unwanted flavors in the next beer. So I'm looking for an occasional alternative, and a small cost saving.

Questions: How much of the dry pack should be saved? How long and how much DME should be used for a starter to get a sufficient yeast count? Will I get a sufficient yeast count?

Thanks folks for any insight or criticism.

 

[HaDaL]

When You open a dry yeast sachet,You should use It as soon as possible within a few days.You'll ask:Why?! Why should not I use a saved opened yeast pack when I am going to make proper starter and will get enough yeast cells anyway?
Answer: You can multiply the cell numbers by one or several starter(s) but You may not reproduce the cells with the characteristics similar to the initial yeast.In fact when You open the sachet, pick some yeast up and close it again, It is exposed to the oxygen and moisture anyway no matter how fast You are.Thus the yeast cells will get up and need food.At first they consume their own stored food and when It is finished they start eating each other and what We call autolysis will occur.Living in unsuitable conditions besides the loss of cell numbers,genetic mutations occur, and thus it is likely the characteristics of initial yeast be changed.That is why You use such a yeast and see unusual events like too low/too fast flocculation or low alcohol tolerance or flavour problems etc.
IMO,the best alternative for your situation is; making a little bigger starter by a whole yeast sachet,saving a portion(about 100 billion cells or so) of It in the fridge for next batch and pitching the rest in beer.You can use online calcs like this to do the needed calculations.

 

[yeahfairly]

If you are only using a portion of one pack of dry yeast you would likely be under pitching for 5 gallons of wort. If you are looking at saving money on yeast there are several good threads on proper harvesting techniques on here. You could benefit from starting out with a good quality yeast or from making slants from your favorite commercial brew. On the other hand, if you figure equipment costs into the equation..... you can buy an awful lot of dry yeast packets for the cost of stir plate, flasks, DME, glass tubes and the such.... not to mention the labor involved.

 

[Mike_kever_kombi]

Here is what I have done in the past, and it has worked out fine.

At boil, before any hops additions take a sanitized jar and add a quart or so or boiling wort. Set it on the counter to cool while you continue to brew. Once you have finished brewing, and are starting to cool wort, put the jar in some cool water if it is still greater than 80 degrees.

When you go to pitch your dry yeast, hold back a little and put that in your jar of wort. Just make sure the wort is less than 80 degrees. Throw some sanitized foil on jar, or transfer to a flask and stir plate. In 2 days, you have a starter that can be stepped up or refridgerated for a few weeks, then stepped up.

 

[jonpecan]

Thanks for the responses, all.

HaDal: I have used yeast cakes in the past - but have been concerned about transferring some flavors from weirder and stronger beers. I've read some threads suggest folks have stored the unused yeast without incident (some by wrapping up the packet, or sealing in some other container, etc etc) hence this theory. But the mutation concept you bring up is something I hadn't heard of and to consider.

Yeahfairly: I always thought dry yeast packs were pretty much a solid amount of yeast for a pitch. Whereas liquid is generally far less, but still sufficient in most cases. I'm surprised then that only keeping a fraction from the dry yeast pack is an underpitch, but I'm open to the idea.

Mike: Nice strategy, might try it, thanks!

 

[HaDaL]

Brewing is not 100% predictable since at least two main living organisms are present here and work together,Yeast and the human that both of them are somehow unpredictable.Based on brewing science We can say some general sentences like I said about the autolysis and possibility of genetic mutations but conversely,when someone says "I've used old opened yeast sachet with success",We must keep in our mind that firstly, not every yeast act the same everywhere and secondly,not every man knows the success! You may find some people around here who claim they've brewed amazing beers with bread yeast or with ton of sugars or You may hear about some folks who make great beers with Spontaneous fermentation and similar stories.So IMO, it's better We trust the science and do not do something which is doubt about It.
Harvesting yeast from a starter is one of the easiest and cleanest available methods which does not need yeast washing process while highest quality cells can be cropped in this way for short-term storage in the refrigerator or long-term storage in the freezer.If You have difficulties using yeast calcs to plan the proper starter, I can explain how to manually do the calculations on paper.

 

[z-bob]

I was just wondering the same thing about a liquid yeast smack-pack. Pour the yeast in the primary, but hold back just a few drops. Rinse the packet out with sterile wort and pour into a sterile beer bottle with a sterile stopper and a lock. The plan would be to start a 2nd beer in about a month.

Should the sterile wort (made from DME) be heavily hopped, lightly hopped, or unhopped? (does it matter?) At what point would you refrigerate it? Oxygen seems to me the complication -- reproducing yeast is going to need oxygen, but aerating the wort is likely to contaminate it (in my house, anyway)

Or would it be better to pitch the *entire* packet -- even the last drops -- and harvest some yeast from the primary?

 

[marvin_yorke]

I'd rather consider making like 1.5L starter but pitching only 1-1.25L of it into the wort and saving the rest for the future propagation. The sachet is sealed and once you open it, you cannot seal it back good enough so eventually the yeast will spoil anyway. Making a starter from these weak yeast could probably revitalize it but conserving some known good, fresh and healthy yeast after good and healthy starter fermentation seems more reasonable to me as the vial or jar could be sealed properly and stored in the fridge

 

[ScrewyBrewer]

I've always thought that dry yeast had to be rehydrated in 90F sanitized water before pitching it into wort, to allow the cells to take in water through the thick layer of nutrients the yeast is coated in from the drying process.

I've never heard of making a starter directly from dry yeast because the cells wouldn't be able to intake wort as easily as they would water to become rehydrated. You learn something new everyday, but the practice of making starters using dry yeast isn't something I've read anywhere before.

 

[HaDaL]

z-bob - Every man has his own way! but each way has It's own principles which must be adhered.You can harvest a large amount of yeast from starter,exponential phase in primary(top-cropping),end of primary or end of secondary (bottom-cropping) or You can culture a small amounts of yeast cells on agar slants or plates.Also You can choose between several storing techniques to save the yeast for a short or long time period.If You want to save some yeast from a smack-pack IMO,It is better idea making a proper starter with It,use a portion for current brew and save a portion of that for next brew(or save it with other storing techniques).Your plan dose not work for harvesting and storing enough yeast since there are very few cells in remaining drops of a pack and It needs several starter for stepping it up.You can not propagate drops of liquid yeast in more than about 10 ml wort at first step.The wort which is brewed for starter,should boil for just 15-20 min without hops or any adjuncts and It's SG should be around 1.030 to 1.040 .Oxygen is the most important nutrition for yeast cells during their growth phase and as You know our aim of making starter is just growing more healthy cells so It will have better qualitative and quantitative results If oxygen be always available to the yeast cells during the whole process and also co2 can leave the starter vessel easily. That is why using stir plate raise the growth factor significantly and preferred by brewers.

ScrewyBrewer - I think no one here said that dry yeast must be pitched directly without rehydrating though It can be pitched directly even some manufacturers of dry yeast in their product instructions say that it must be pitched directly but We know this is not ideal for cells to be awakened in high-density environment which can injure the cell membrane.Although compared to the typical main wort,starter wort is simpler with a lower sg. However, You are right when You say "

but the practice of making starters using dry yeast isn't something I've read anywhere before"

.In almost all resources of home brewing literature,authors have mentioned that harvesting and reusing yeast from a dry yeast propagation is not reasonable because dry yeast is so cheap and available all times and also there are enough cells in one sachet of dry yeast to ferment the typical home brew batch.But They've not considered that there are some places in the world that even one sachet of dry beer yeast is rare and very precious and there are some people who can not obtain liquid yeasts of different strains or even different types of dry yeasts. They have to save the yeast which is not valuable from the point of view of those authors.