Opened yeast pack and froze remaining. Still good?

It sounds like at least some of the yeast survived. As for worrying, at this point there's really nothing to do but wait and see how the beer turns out.

 

I'm not really a dry yeast guy, but I believe most manufacturers recommend storing airtight, in the fridge.

 

Below is what Fermentis publishes on their dry yeast data sheets:

"Opened sachets must be sealed and stored at 4C (39 degrees F ) and used within 7 days of opening."

Cheers!

 

I needed only half a packet of US-05, so had Mr. Foodsaver warming up when I made the incision. It was exposed to air for less than 60 seconds, then vacuum sealed and chilled to 40. About six weeks later I opened to rehydrate and it was as if I poured sand into the bowl of water. It sank to the bottom and never showed a flicker of life. Maybe Belgians are from tougher stock.

Just opened a CBC-1 today and used all of 3.5 grams of an 11g packet. Not bothering trying to salvage the rest.

 

All depends on when the yeast was packaged and the gravity. The older the yeast the less viable it is and the higher the gravity the more yeast you need. I recommend using a yeast calculator to determine how many yeast cells you need. However, generally it's better to pitch more yeast as opposed to less yeast. To me dry yeast is cheap enough even if I pitch half the packet it's not worth storing unless I plan on brewing again asap.

 

My view is that it would be a mistake to pitch the whole packet. At most I would pitch half of it, but even that is a big over-pitch. Maybe 1/4.

But I've never brewed a batch that small, so I can't really say from personal experience.

 

I've not heard anything bad about overpitching, so I wouldn't see an issue with it.

One way to save the remaining yeast is to make a mini wort and salvage the rest of the yeast.
Take some DME hold around 180 for 10 minutes, cool to 70 and put into a sanitized flask or bottle. Cleanly pour in rest of yeast, wait 2 days, pour most of the top off carefully, and the remaining into a sanitized Mason jar. Seal, label and keep in the fridge.

If you are going to rebrew in less than 60 days, just use straight, if more than 60 days, repitch like above and use that.

Should have plenty of yeast and don't have ot keep buying new yeast.

 

Below is from the Wyeast website:

High pitch rates can lead to:

• Very low ester production
• Very fast fermentations
• Thin or lacking body/mouthfeel
• Autolysis (Yeasty flavors due to lysing of cells)

I have no idea whether a full dry yeast sacket in a one gallon batch would result in a poor mouthfeel and/or off-flavors from lysing of yeast cells.

Cheers!

 

I've been doing 1 and 2 gallon batches, and usually use S-04 and S-05. I go off of Mr. Malty and save the leftover dry yeast - Fold up the package, paper clip, and put in the freezer. I just made an IPA using leftover S-05 (5ish grams) that had a expiration of 1/2017 - so open and almost expired. Rehydrated and pitched in 2 gallons at 1.060 SG. No issues with fermentation and no off flavors.

It appears that Mr. Malty usually recommends between 5-6 grams of dry yeast for batches up to about 2 gallons and about 1.070 SG, regardless whether it's one gallon or two, 1.040 or 1.060 SG. Just my perception. Seems wasteful to use the whole packet or to throw out the leftovers.

 

Rehydrating is a good way to keep your yeast healthy, and in most circumstances I would advise it. But in this particular case, I can see an argument for skipping it, since it is simply another thing that could go wrong, and there is no way you're going to underpitch in any case.

There is no concern about airlock activity, the yeast can perform a healthy, vigorous fermentation without creating any airlock activity. It just requires you to be a little more observant, since it will be harder to tell if something has gone wrong.

 

Here's what is going on in your primary:
https://www.morebeer.com/articles/conditioning

Regarding rehydrating; I make 5 gal batches and always rehydrate (dry) or restart (liquid). . . and always have a "spare" packet in reserve. The first time you pitch "dead" yeast into your primary will make a believer out of you.

 

If you were brewing a 5 gallon batch I would recommend that you rehydrate the yeast.

For the case of brewing one gallon batches simple sprinkling 1/2 sachet into the fermentor should be sufficient.

Cheers!

 

Since they are just 1-gallon batches, it seems they would be perfect for experimentation. Could you just do a batch each way and see if there is any difference? 5-10 gallon batches call for quite a lot of drinking commitment if they come out so-so, which is why folks try to optimize everything. I'd think that an advantage of 1-gallon batches is that they are more like test batches anyway, right?

 

For rehydrating vs not rehydrating, there brulosophy ran an experiment, basically no taste difference in the final product. http://brulosophy.com/2016/12/05/ye...hydration-with-dry-yeast-exbeeriment-results/