Home Distiller

So say you have a yeast you want to use and the date has passed. Many would think this yeast is too old and that it will never be any good as old as it is. Well maybe, but maybe not. A yeast that has been expired this long can most likely be brought back to a healthy life with a little care.
First I made a starter using DME with an OG of say 1.030 (1/3 cup of DME to 1 pint of water to give it a gentle wake up call. Boil this for 10 minutes and cool then add your out dated yeast. Typically you'll notice no effect but this doesn't mean the jig is up. I put this starter on a stir plate at a low setting and leave it overnight, say 10-12 hours all together. I should also mention that the bottle or jar used should be washed clean and sanitized. I usually use Star-san but other sanitizing agents or methods are equally as effective. After this time has passed I add a second starter a little stronger say, 1/2 cup DME to a pint of water (OG 1.040). in the meantime I've turned off the stir plate and let the yeast settle. Clear liquid will rise to the top. Pour off the clear liquid and save the sludge at the bottom. This will end up being your live yeast. add your new starter to the yeast. If you don't have a stir plate just give your starter a gentle swirl every now and then. the idea is to keep the yeast suspended and not lazy/ dormant. After 6-8 hours you should see the light fizzle going on. Keep giving it that swirl.

About this time I want to get a little more serious about where this yeast is going so I make up a small mash to make even a bigger third starter. This yeast will be for an Irish Whiskey I had planned to make but time seemed to move faster than I did.
First I added the grains I would be using to make this whiskey. Approximate amounts are fine as long as you can get an OG of say 1.060. We want to put some weight on this weak ass yeast. I used a scoop and added one scoop of 2 row, 1 scoop of 6 row, 2 scoops of raw barley and a half scoop of oats. This will be my approximate recipe. Also, to assure the yeast will be happier with this mash I add a vitamin B tablet. I weighed my grain and used 2lb:1gal/ grain to water ratio then set it on my hot plate aiming for a mash temp of 150ish. To be sure the mash will be best suited to feed this yeast we aim for a PH of 5.4-5.6, at room temp 5.2-5.4. This looks good to me. I continued mashing for an hour finally seeing may syrupy goodness start to show at the surface of my pot. I think this mash is done. I let it set until it cools to about 130F. After this your not getting any more benefit so I cool it in a sink of water until is warm to the touch. I sanitize another pot and colander w/star-san. You can also put the pot and colander in the oven @ 300 for a spell and probably get it just as sanitized as long as you don't touch the insides but Star-san was on hand and was quicker. I place the colander over the pot and pour my mash into it separating the grain from the liquid. Using the pot I cooked the mash in I press the grain a bit to push any extra liquid out I can get. While I was waiting for the mash I cleaned and sanitized a gallon jug (1/2 gallon of starter was the size I was after). I add my starter to the gallon jar then go back to my stir plate and get the bottle of active yeast we resurrected earlier. I add this yeast to the larger starter putting the bubbler firmly in place. I store this at a 72F location as this is the approximate the center of the yeasts temperature range. Within hours it was bubbling away just as if I bought it that day. Really amazing that a yeast I had been holding in the fridge for almost 2 years could be easily brought back in a short couple days.

Once the yeast started to slow its bubbling action I went ahead and placed the gallon jug in the fridge as I wouldn't be able to get to mashing my whiskey right away. I hope to get to it sometime this year though...
I'll pull it out when I'm ready and warm the starter. It'll get to bubbling again at 74F I expect. Then I'll pitch it.

Nice write up. I do it all the time. I have a frozen yeast bank and a step starter ensures a healthy supply of yeast.

Nice job, but I have a question. All you have done, in terms of time, work and money, is it worth while? was it some precious yeast strain never to be found again?