Author Topic: Yeast Package Date  (Read 5672 times)

Offline Mr. Beer

  • BeerSmith Apprentice Brewer
  • **
  • Posts: 8
Yeast Package Date
« on: November 25, 2014, 11:33:01 PM »
I noticed that in the yeast section there is a package date that either defaults to 2/27/2011 or 3/6/2011. It's easy enough to enter the date, but when you use the calendar you have top scroll forever. Maybe it would be better to have the default package the current date. I was also thinking it might be advantageous to have a field that you could enter the best by date, which is what white labs and wyeast stamp on the packaging, that way it could calculate the actual package date.

KernelCrush

  • Guest
Re: Yeast Package Date
« Reply #1 on: November 26, 2014, 03:04:40 AM »
Agree dates can be a pain to change.  You should be able space bar or tab to day month year instead of the dreaded click-and type.  But you can look down at the bottom of the calendar and click on the bottom line that says 'today's date' and it will fill in...its less painful to do the calendar scroll then. 

For White Labs you have to back up 4 months from the date stamp and that gives you the actual date it was packaged.  Wyeast date stamp is the date is was packaged and you have to add 6 months to get the 'best before' date. 

Offline graymoment

  • BeerSmith Brewer
  • ***
  • Posts: 33
Re: Yeast Package Date
« Reply #2 on: December 03, 2014, 05:31:56 PM »
It would be nice if there was a "best by date" for White Labs yeasts. It would also be helpful if the viability calculator followed the same trajectory that the manufacturer gives for their yeast. Maybe this is more of comment about yeast manufacturers than it is about Beersmith's calculator.

When I called White Labs, they told me that the best by date is the date in which they guarantee the viability for a 5 gallon pitch into wort under 1.060 specific gravity. Obviously, that's hugely different than what the yeast calculator would suggest in Beersmith (which shows hardly any viable yeast left in the package by the best by date, and even a big starter wouldn't get you enough cells for calculated total cells needed.

Offline MaltLicker

  • Global Moderator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 2004
    • Blue Ribbon Brews
Re: Yeast Package Date
« Reply #3 on: December 04, 2014, 08:36:51 PM »
My [dated] understanding is that White and Wyeast generally simplify to 20% per month loss of vitality as a flat rate.  After five months, not worth using it.

Brad prefers the more biologically accurate approach of 20% per period (month).   So each month the loss after Month One is increasingly less than 20%.  Theoretically, this extends the package life to 10 or 11 months, but neither major MFR vouches for that duration.   And if you factor in poor storage and shipping conditions, five months seems safer.   

Offline mm658

  • BeerSmith Master Brewer
  • ****
  • Posts: 58
Re: Yeast Package Date
« Reply #4 on: December 05, 2014, 09:11:42 PM »
A similar but different discussion I started a couple of years ago:
http://www.beersmith.com/forum/index.php/topic,7584.msg30390.html#msg30390


Offline MaltLicker

  • Global Moderator
  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 2004
    • Blue Ribbon Brews
Re: Yeast Package Date
« Reply #5 on: December 07, 2014, 08:30:38 AM »
Thanks for finding and re-posting that.  Tom's final post sums it up nicely. 

White and Wyeast (and JZ) have each done the cell counts and their model for vitality seems the best fit for reality, and the yeast MFRs are also the ones that have to back their yeast products, and have in their mutual best interest with homebrewers to have a successful brew day. 

I do wish Brad would adopt the more realistic yeast vitality models into BSmith so that users would not be forced to go outside the program for the estimates that all the yeast experts agree better match reality. 

 

modification