Dry Yeast Pitch Rate and Bulk Dry Yeast

[Carolina_Matt]

I wonder; why? This would make useless my initial idea of buying dry yeast in 500g bags. I suppose I could by the sachets in bulk...

Hey, wait a minute... now that I think about it; I've been using the same batch of dry yeast for bread making for over 3 years - it just sits in an airtight container in my freezer - and those loaves come out just fine. Couldn't the same apply for US-05 or any other strains of brewer's yeast?

When I was considering bulk dry yeast, I saw plenty of people that vacuum sealed it and put it in the freezer. I don't think that should be an issue.

 

[Robert65]

I've been head scratching over the "use in 7 days" bit too. I likewise buy bricks for baking and just keep it in a Mason jar in the fridge with no issues. I wondered if the concern (especially for commercial brewers) was the possibility of contamination once open, but can't see how a week or a minute presents a different risk if there's a risk at all. Maybe they just want you to throw it out so you'll throw another couple Benjamins at them sooner.

And as for repitching 5 times... dry yeast is no different than liquid yeast in this respect. Once pitched, it is a liquid culture. There is no number of generations you can go that is set in stone. You might go dozens of generations, or indefinitely, or only one or two. It's mainly dependent on the yeast and the conditions it experiences (oxygen, nutrients, alcohol, handling and storage....) If you like the job it's doing, reuse it. As soon as you're dissatisfied, replace it.

 

[ncbrewer]

Any chance that you will put some/most/all of your Q&A with them into a single post that can be referenced in the future?

By popular demand, here is the info I got from Fermentis:

1-11-20 ME: Your FAQ page answers the question "I see the recommended rehydrate temp for ale yeast is 25~29°C? My pitching temp for ale is 18°C. Will this not "stun" the yeast?". The Tricks and Tips page states "The temperature of the hydration media is between 10 and 28°C (50-82,4°F); and should ideally be close to fermentation temperature." This is lower temperature than the previous recommendation, and lower than shown on the FAQ page. It the lower temperature range a new recommendation?

1-13-20 FERMENTIS: Thank you for contacting Fermentis. All our strains can be direct pitch into the wort, as long as the wort is between 10 to 28°C. That will not affect the yeast viability, vitality and resulting beer. If you want to rehydrate the yeast, also do it between those temperatures.

This is the latest information we have on our strains based on the latest trials. I apologize that there still is some potential confusing information in our written documentation.

1-14-20 ME: Thanks for the explanation.

I'm planning on pitching direct (dry) for my next batch. But I use top-off water, which I stir in before pitching. (In order to get 65F overall pitching temperature, the top-off water can be much colder or warmer than the wort from the kettle, depending on the season.) This prevents me from exactly following the instructions in the Tips and Tricks section: "To do so we recommend using the necessary quantity in weight of ADY and to put it into the fermentation vessel during the first part of the wort cooling step." The surface is very foamy. I'm concerned about sprinkling the yeast on the foam and leaving it, and my concern about contamination prevents me from waiting 10 minutes before stirring. I think gently stirring the yeast into the wort immediately after pitching would approximate the results that the instructions call for. Would this be correct?

1-14-20 FERMENTIS: Direct pitching is the method with the lower chances of contamination as there is no yeast handling prior pitching. But, in your case, with the presence of foam on the surface of the liquid is for sure not ideal. Sprinkling the yeast on the foam will leave some yeast outside of the liquid which is no good. I will definitely rehydrate the yeast with water or wort in a sanitized container and pitch that slurry. If you stir, remember that is has to be gentle, max 100rpm on a stir plate or equivalent. Agitation (over 100rpm) during rehydration is the main cause of loss of viability in the yeast.

 

[BrewnWKopperKat]

I've been head scratching over the "use in 7 days" bit too.

If it were a $5 package of yeast, I'd mention that many small batch (and one gallon batch) probably use partial packages. Personally, for my one gallon batches, I pitch a quarter package & put the rest in the fridge for another batch (rubber band to close it tightly, others probably vacuum seal the package). Yup, the beer comes out fine.

But 500 gram bricks appear to be around around $100 and I have no experience with this type of packaging. Maybe it scales up, maybe to doesn't.

 

[dmtaylor]

I wonder; why? This would make useless my initial idea of buying dry yeast in 500g bags. I suppose I could by the sachets in bulk...

Hey, wait a minute... now that I think about it; I've been using the same batch of dry yeast for bread making for over 3 years - it just sits in an airtight container in my freezer - and those loaves come out just fine. Couldn't the same apply for US-05 or any other strains of brewer's yeast?

I just used a partial pack of S-189 that was in the refrigerator for 2 full years, and it started up just fine within 24 hours. Not vacuum sealed, no rehydration, no problem.

 

[foolsbrew]

I wonder; why? This would make useless my initial idea of buying dry yeast in 500g bags. I suppose I could by the sachets in bulk...

Hey, wait a minute... now that I think about it; I've been using the same batch of dry yeast for bread making for over 3 years - it just sits in an airtight container in my freezer - and those loaves come out just fine. Couldn't the same apply for US-05 or any other strains of brewer's yeast?

I just used a partial pack of S-189 that was in the refrigerator for 2 full years, and it started up just fine within 24 hours. Not vacuum sealed, no rehydration, no problem.

I think the core reason is companies playing it safe honestly. Almost every other product in general lasts way longer than their supposed expiration date too. It's not like the rest of the pack is exact. These numbers are just what they deem to be safe with no risk of getting sued.

 

[BrewnWKopperKat]

I think the core reason [use opened packages quickly] is companies playing it safe honestly.

https://www.lallemandbrewing.com/en/united-states/products/brewing-yeast/ has a "storage" tab which offers a summary explanation. Recent (didn't see it in the current Fermentis information) information for Fermentis was similar. I'm only looking at yeast labs this time - but the last time I looked, advice for MJ branded yeast would be similar.