Do you know how to make a yeast starter? Then why not farm yeast and freeze it?

[BBL_Brewer]

The freezer above my fridge hovers around -17 degrees F and spikes up to around 0 at periodic intervals (the frost free side of it I assume). My deep freeze only runs at -6 F but sustains it very well. That's only when it's near full. The fridge unit is rarely more than 1/4 full but the top shelf of my fridge will also freeze items solid as well. I made the mistake of storing yeast there once... Only once.

Use your deep freeze for storing frozen yeast, that will give you the longest shelf life. If you absolutely have to use the freezer above your frige, then store the yeast in a small cooler with some ice packs if possible.

 

[Hermit]

The freezer above my fridge hovers around -17 degrees F and spikes up to around 0 at periodic intervals (the frost free side of it I assume). My deep freeze only runs at -6 F but sustains it very well. That's only when it's near full. The fridge unit is rarely more than 1/4 full but the top shelf of my fridge will also freeze items solid as well. I made the mistake of storing yeast there once... Only once.

I was in appliance repair over 30 years. -17F is pretty cold for a top mount freezer. Zero has been the recommended and industry standard for a long time. I recently 'worked' on one for a friend who said his freezer just wouldn't stay cold enough. The problem? His thermometer. Freezer was fine. At -17F I kinda doubt your thermometer to be honest. Possible but unlikely you maintain that temp depending on the age of the unit. The newer the unit the less likely that it has that much over capacity.

 

[Accidic]

The thermometer flickers between 1 and 0 in a bowl of ice water so it's probably a tiny bit off but it seems solid otherwise.

I used to use the deep freeze but it is opened a heck of a lot more and can be 1-2 degrees above 0 for more than an hour. IE, it's old. The only thing the top freezer is used for is storage of certain food items so I use it for the only 3 samples I keep. I keep them sealed in a thermos I drilled, filled 90ish percent full of chillpack gel, and replugged. This seems consistent with the manu's claims that it freezes between 8-10 degrees below. The cooler would probably work too but I got the thermos free and it fits perfectly in the bottom corner of that freeze plus is airtight and I'm not truly convinced the lids on my vials actually are. Also, as a sidenote, I can turn the dial on my fridge down to get closer to zero (lowest is actually -1 on my thermo) and it freezes ice at that temp without issue. But I make my own Ice Cream and I like it to stay nice and hard (much to my wife's chagrin).

 

[el_caro]

I do not have time to read all the posts on this thread at the moment so excuse me if this has been previously addressed.
I would like to give this a shot and have a bottle of Faulding (Remedies) Glycerine which seems to be 100%Glycerol.
It is described as an application for roughened skin. Faulding customer support told me that they do not recommend its use in cooking (making icing etc) as it can cause dehydration if ingested in other than very small amounts?

Would it be ok to use this for freezing yeast? Had a look in the supermarket but glycerine seems harder to find than rocking horse manure.

 

[BBL_Brewer]

I keep them sealed in a thermos I drilled, filled 90ish percent full of chillpack gel, and replugged.

I like the gel idea. So it's just a container filled with gel and holes for the vials to slip into?

 

[BBL_Brewer]

I do not have time to read all the posts on this thread at the moment so excuse me if this has been previously addressed.
I would like to give this a shot and have a bottle of Faulding (Remedies) Glycerine which seems to be 100%Glycerol.
It is described as an application for roughened skin. Faulding customer support told me that they do not recommend its use in cooking (making icing etc) as it can cause dehydration if ingested in other than very small amounts?

Would it be ok to use this for freezing yeast? Had a look in the supermarket but glycerine seems harder to find than rocking horse manure.

You want to use food grade vegetable glycerine. If they tell you it's food grade then go ahead and use it, but if it's not, then I would find something else. You can order it off the net. That's what I do. I just get a gallon at a time and it lasts forever. A good brand is "Now" It's made here in the United States. Be careful about ordering glycerine made in China.

 

[el_caro]

Thanks BBL - Will take your advice and look on the net.

 

[el_caro]

Another stupid question but there are so many figures floating around on this thread that my head is spinning.

Is the general consensus that if I wish to make a pint (473ml) of glycerine solution to add to the yeast - then the glycerine solution should be made with 131 ml glycerine to 342ml of water and then the ratio of yeast slurry to glycerine solution should be 50:50 ?

 

[BBL_Brewer]

Another stupid question but there are so many figures floating around on this thread that my head is spinning.

Is the general consensus that if I wish to make a pint (473ml) of glycerine solution to add to the yeast - then the glycerine solution should be made with 131 ml glycerine to 342ml of water and then the ratio of yeast slurry to glycerine solution should be 50:50 ?

I've had the best luck with a final concentration of ~18-20% v/v. In other words I mix 131 ml of glycerine with 342 ml of water and then mix that solution between 70:30 and 65:35 with my yeast slurry. 65-70% glycerine solution and 30-35% slurry. There still seem to be varying opinions on this, so you might want to experiment a little, but the general consensus is that you shouldn't need any more than that.

 

[Accidic]

I like the gel idea. So it's just a container filled with gel and holes for the vials to slip into?

No, it's actually a thermos with the outer layer drilled to allow the gel to fill it and I insert the vials into the container. I had some rubber plugs from god knows what laying around that filled the hole perfectly without problem. The lid to the thermos is an airtight screw on lid. I glue small disc magnets onto the tops which makes retrieving them very easy with a telescoping magnet.

Admittedly the gel (I used Easychill IIRC) reduces the effectiveness of the thermos effect slightly but it does have a few other benefits. For one, the gel has to melt before it drops below 0. Even if it's not frozen completely, it's still frequently colder than 0 degrees (limited to the freezer's lowest temperature of course) and this cools the inner chamber of the thermos reducing the ways for heat to get into the vessel as it hypercools the metal connection to the inner chamber at the lid level (if that makes sense). And finally most importantly, the metal cylinder ensures that if one of the vials were to explode or get broken, the glass would be safely segregated from the rest of the freezer meaning the wife is much more complacent about one of my many "projects." Admittedly I cannot provide evidence that this works any better than using a small cooler but I would think it more efficient and if nothing else it takes up far less space in our freezer. The thermos I have is a promo item I got for free and I can actually comfortably fit 9 of my current vials in it with a small amount of headspace at the top. I guess I could look into filling the container with glycerine which in it's raw form would not freeze (at least in my freezer) barring heavy dilution but it just seems like overkill.

 

[Accidic]

Sidenote, out of curiousity regarding the comments about temp yesterday... I'm testing the temp in my freezer presently by freezing glycerine & water mixtures. 25/75 froze fine in the freezer but not the chest freeze. I mixed up a 40/60 mix and replaced the frozen one this morning. I figure if that one turns the thermometer is at least marginally accurate since the freezing point should be ~16 degrees below or my scale is off...

 

[BBL_Brewer]

No, it's actually a thermos with the outer layer drilled to allow the gel to fill it and I insert the vials into the container. I had some rubber plugs from god knows what laying around that filled the hole perfectly without problem. The lid to the thermos is an airtight screw on lid. I glue small disc magnets onto the tops which makes retrieving them very easy with a telescoping magnet.

Admittedly the gel (I used Easychill IIRC) reduces the effectiveness of the thermos effect slightly but it does have a few other benefits. For one, the gel has to melt before it drops below 0. Even if it's not frozen completely, it's still frequently colder than 0 degrees (limited to the freezer's lowest temperature of course) and this cools the inner chamber of the thermos reducing the ways for heat to get into the vessel as it hypercools the metal connection to the inner chamber at the lid level (if that makes sense). And finally most importantly, the metal cylinder ensures that if one of the vials were to explode or get broken, the glass would be safely segregated from the rest of the freezer meaning the wife is much more complacent about one of my many "projects." Admittedly I cannot provide evidence that this works any better than using a small cooler but I would think it more efficient and if nothing else it takes up far less space in our freezer. The thermos I have is a promo item I got for free and I can actually comfortably fit 9 of my current vials in it with a small amount of headspace at the top. I guess I could look into filling the container with glycerine which in it's raw form would not freeze (at least in my freezer) barring heavy dilution but it just seems like overkill.

Oh, ok. I guess I misunderstood.

 

[Accidic]

If you were more crafty you could sand cast a mold fit to the vials, spray it with plastic and fill it with gel alternatively and just seal it with insulated lid. I'm not nearly that crafty though. The price on the thermos was right (free), I had the gel extra from shipments of yeast just sitting around, and I had the plugs and magnets sitting around collecting dust so it kind of just came together since I needed something smaller than a small cooler to keep the peace in my house.

 

[el_caro]

I've had the best luck with a final concentration of ~18-20% v/v. In other words I mix 131 ml of glycerine with 342 ml of water and then mix that solution between 70:30 and 65:35 with my yeast slurry. 65-70% glycerine solution and 30-35% slurry. There still seem to be varying opinions on this, so you might want to experiment a little, but the general consensus is that you shouldn't need any more than that.

Thanks again BBL for the quick response and thanks to all who have made this a really great thread that I think should be considered for a sticky.

 

[JFK]

Someone in my brew club brought up a concern that I did not have an answer for. He said and I'm quoteing not stateing according to whites book there is mutation that occurs at -20 storage that does not occur at -80. Is this true and if so how will it effect my brew.

 

[Golddiggie]

Someone in my brew club brought up a concern that I did not have an answer for. He said and I'm quoteing not stateing according to whites book there is mutation that occurs at -20 storage that does not occur at -80. Is this true and if so how will it effect my brew.

You'll be making "Mutenbrau"...

 

[Brewitt]

It is true that yeast are more stable at -80C but there is no specific mutation that occurs at either temperature that I am aware of. In fact, mutations occur more slowly in the cold and especially below freezing. The reason for the additional stability is that the colder conditions are both better for preserving cellular structure and preventing chemical change. My recommendation would be, don't worry about it.

 

[Golddiggie]

I need to thaw out one of the tubes I put up and see what I get. I already know I'll need to make a couple/few starters to get the cell count needed. Just need to have the free time to brew. Believe it or not, even when between jobs, you don't have as much 'free time' as you would think.

 

[Accidic]

Seems like you'd have less time between jobs due to being forced to look for the next job.

 

[theveganbrewer]

It doesn't have to be this difficult. What I reccomend is that you put all of your yeast slurry into a large container with volume markings. Add your glycerine solution and any top of water if needed, then split it up into whatever you're going to freeze in. Unless you're using a centrifuge, there's no reason not to. I have marks on my starter vessels so I just do it in there. I know what I want my final vomue to be (500 ml) so I use the following equation: Final Volume x Desired Glycerine Concentration (%) / Concentration of Glycerine Solution

So for example Let's say 500 ml final volume, 15 % v/v final concentration, 60% glycerine solution. (500 x 0.15) / 0.6 = 125 ml of 60% glycerine solution required.

Add your 125 ml, top off with sanitized water.

I am still frustrated with this formula. I don't know what my final volume is going to be, how does anyone know that?. I need the formula for figuring out how much glycerine solution is require for a specified amount of yeast slurry. What is that?

Is this correct?

Yeast Slurry Volume / 0.30= Total Volume
Total Volume * 0.7= Glycerine Solution Volume
Glycerine Solution Volume *0.6= Glycerine Volume

 

[Golddiggie]

I am still frustrated with this formula. I don't know what my final volume is going to be, how does anyone know that?. I need the formula for figuring out how much glycerine solution is require for a specified amount of yeast slurry. What is that?

Is this correct?

Yeast Slurry Volume / 0.30= Total Volume
Total Volume * 0.7= Glycerine Solution Volume
Glycerine Solution Volume *0.6= Glycerine Volume

You're thinking about it too hard/much... Once the starter is done, you can cold crash it, or let it settle long enough, to get a volume measure in your flask. Then use that to determine how much additional glycerine solution to make up, and at what concentration, to get your freeze-ready slurry made.

I picked up a set of graduated beakers after the first batch was in the freezer, for use next time. That will go a long way to helping me to get where I want to be (higher accuracy than the flask).

I'm looking to use one of the frozen tubes of yeast for my next batch. Just have other things going on in the basement (shop and brewery) right now. Once that stuff is finished, I'll be able to brew there again.

 

[BBL_Brewer]

I am still frustrated with this formula. I don't know what my final volume is going to be, how does anyone know that?. I need the formula for figuring out how much glycerine solution is require for a specified amount of yeast slurry. What is that?

Is this correct?

Yeast Slurry Volume / 0.30= Total Volume
Total Volume * 0.7= Glycerine Solution Volume
Glycerine Solution Volume *0.6= Glycerine Volume

In the example that I gave, I already had a jar of 60% glycerine solution sterilized. The formula I provided tells you how much of that 60% solution I had to mix with my slurry in order to hit my target volume and target final glycerine concentration. If you are working with pure glycerine, it's a lot easier. Decided what you want your final concentration to be. I've been going with 20% by volume. Then you decide what you want your final volume to be. Final volume * .20 = volume of glycerine needed.

 

[theveganbrewer]

These numbers are all jumbled to me. Unless they're written in a formula, math does not make sense to me. Why there is no formula here using yeast slurry to figure out the other numbers? You said, "you decide what you want your final volume to be." How? I am given the slurry, I don't have any say in how much the final volume will be, it's got to be based off that slurry volume, doesn't it?

Where are you getting 'final volume' from? I'm sorry I'm so dense, but this just doesn't make sense to me.

 

[theveganbrewer]

You're thinking about it too hard/much... Once the starter is done, you can cold crash it, or let it settle long enough, to get a volume measure in your flask. Then use that to determine how much additional glycerine solution to make up, and at what concentration, to get your freeze-ready slurry made.

I picked up a set of graduated beakers after the first batch was in the freezer, for use next time. That will go a long way to helping me to get where I want to be (higher accuracy than the flask).

I'm looking to use one of the frozen tubes of yeast for my next batch. Just have other things going on in the basement (shop and brewery) right now. Once that stuff is finished, I'll be able to brew there again.

That was my question, how do you figure that out? Can you provide a formula? If I have 200 ml of slurry, how can I plug that into a formula that tells me how much glycerine and water to use?

 

[BBL_Brewer]

That was my question, how do you figure that out? Can you provide a formula? If I have 200 ml of slurry, how can I plug that into a formula that tells me how much glycerine and water to use?

You're way overcomplicating this. I'll see if I can walk you through this.

Final volume is how much liquid you end up with after you mix in the glycerine. Here are a few examples that should help.

Scenario 1

You have 150 ml of yeast slurry. You want to know how much glycerine to add so that the final concentration is 20% by volume. Working with percents is kind of weird. We're shooting for 20% glycerine, so we have to divide the volume of slurry we have by 80% to find out what the final volume would be with 20% glycerine mixed in. If we wanted 30% glycerine, then we would divide by 70%, Here is the equation.
Volume of Yeast slurry / 0.8 = final volume. We have 150 ml of slurry. 150 / 0.8 = 187.5 ml. Now that we know the final volume, we can subtract the amount of slurry we already have (150 ml) to determine how much glycerine we need. 187.5 - 150 = 37.5. So, you add 37.5 ml of glycerine to the 150 ml of slurry that you already have and then freeze it. We now have a final concentration of glycerine of 20%. 37.5 / 187.5 = 0.2

Scenario 2

You have 150 ml of slurry. You want to use this slurry to fill (5) 100 ml vials. You want a final concentration of glycerine of 20% by volume. In this instance, we know what the final volume is going to be, 500 ml, becasue that is what we need to fill all the vials. Here is the equation for this one.
Desired final volume * desired glycerine concentration % = glycerine needed. 500 ml * .20 = 100. So, we add 100 ml of glycerine to the yeast slurry we already have and then add water to top it off at 500 ml. Then you fill the vials and freeze.

Scenario 3

You have 150 ml of yeast slurry. You want to use this slurry to fill (5) 100 ml vials. You want a final concentration of glycerine of 20% by volume. You have a pre-sterillized jar of 60% by volume glycerine solution. You want to know how much of the 60% solution to add to your yeast slurry. Here is the equation.
(Desired final volume * desired glycerine concentration %) / concetration of existing glycerine solution = glycerine solution needed

Our final volume is going to be 500 ml because that's what we need to fill the vials. We want 20% glycerine. Our pre-sterilzed glycerine solution is 60% by volume. (500 ml * 0.20) / 0.60 = ~167 ml. So, we add 167 ml of our glycerine solution to the 150 ml of yeast slurry that we already have. Then we top off with water to get 500 ml. Then fill the vials and freeze them.

Hopefully that helps, I'm not the greatest at explaining things sometimes.

 

[theveganbrewer]

Thanks man, got it. The 60% solution was what was killing me. I messed up a batch last night because of that. I'm just going to do the 1st one (yeast slurry/0.8)-yeast slurry=glycerine volume.

 

[Golddiggie]

I have notes on how much slurry in the container and how much glycerine solution (at the percentage) to add. I think I even posted it up in this thread back when I was doing the first batch.

I hope you have a fairly accurate way to measure the different aspects/solutions. I don't think being off by a few ML will be bad, but you don't want to drift too far.

 

[JFK]

Formula for dummies. Like the book series. If you use 100 ml of slurry you use 100ml of solution which is 7 parts sterile water to 3 parts glycerol mixture so 70ml water and 30 ml glycerol.

100ml slurry = 70ml water + 30 ml glycerol.
Freezer product =100s +(70w+30g)

 

[el_caro]

Formula for dummies. Like the book series. If you use 100 ml of slurry you use 100ml of solution which is 7 parts sterile water to 3 parts glycerol mixture so 70ml water and 30 ml glycerol.

100ml slurry = 70ml water + 30 ml glycerol.
Freezer product =100s +(70w+30g)

Thanks for that JFK. I like the dummies approach to things involving figures.

Your figures do vary from BBLs suggested ratios and will result in 15% Glycerine as opposed to BBLs 20%. Guess either will be ok.

Have just finished freezing some yeast using BBLs suggested ratios so will wait 3 months and see how they survive.

The piece of equipment I found most useful was a 250ml boro glass measuring cylinder which allowed me to accurately measure the volumes of glycerine, water and yeast slurry.

 

[gwapogorilla]

Hey guys...I don't have a pressure cooker, so would boiling all of my containers for 10 minutes be okay?