yeast sachet lifespan in fridge?

[zipmont]

A few weeks ago I started a ten gallon batch of mead with Cote Des Blanc yeast (just purchased) and another five gallon batch with D47 (age unknown, but at least one year old refrigerated, maybe more ...), both well nourished and pH adjusted to around 3.7. The D47 batch never took off while the Cote batch progressed normally. So I took 5 gallons from the Cote batch and put it in the other. Sure enough, it began to ferment, but is going slowly due to low yeast population it would seem. Will the yeast colonize quickly enough on their own or would it be better to pitch more to get the numbers up quicker?

Last, is there any sort of consensus on how long yeast stay good (unopened) in the fridge? I guess from now on I will err on the side of caution.

Thanks in advance.

 

[Yooper]

It should be fine. The yeast reproduce well, and quickly, and it sounds like it's going well.

Yeast packages, unopened, last for years in the fridge. There is an expiration date on them, but I've used them past the expiration date with no issues.

 

[Bearmaul]

Basically what Yooper said. Keep in mind yeast are microscopic critters and they take time to establish a good colony.

 

[zipmont]

Thanks guys. Any idea why the D47 batch went through week 1 with no change in gravity at all while the Cote Des Blanc went from 13% to 11%? I realize D47 requires lots of nutrition, and the honey in question (orange blossom) is notoriously low in both ash and nitrogen. But I did feed both nutrient and energizer at a rate of 1/2 tsp per gallon, so no gravity change whatsoever for a full week seems weird, especially considering the pH was adjusted several days in after it began to plummet. Could it be that D47 needs that much extra nutrition? Perhaps I should feed D47 at 1 tsp per gallon instead of 1/2? I just don't know what else it could be.

 

[Walking_Target]

If it's old, it takes a long time to start. If i'm buying expired yeast, i'll pitch double what i usually would.

 

[jonmohno]

I like to aerate 2X a day for up to 5 days while adding nutrient daily,like many do and it sounds like yours could have used the help if you didnt aerate. If your starting gravity was high that could be it too. If it didnt start already I would consider putting another pack in,but you added some must from the other sounds like. I would just areate it daily til about 1/2-2/3 ferment or at least a few days.

 

[zipmont]

Thanks for the replies. It sounds like it has to be either a matter of insufficient viable yeast cells, insufficient nutrition, or both.

I guess I need to be more religious about checking dates on sachets. And feed orange blossom honey well, especially when paired with D47!