Buying Yeast Online and Temperature during Transit

Question

I buy everything from Northern Brewer and it takes UPS 5 days to ship to me (If I'm not home early enough from work on Friday, I have to wait the weekend too).

Next week is going to have three days over 90*F in my town.

NB ships all yeast with an ice pack and state that they guarantee their yeast will arrive fresh.

Even if the yeast gets "injured" due to temperatures during shipment, will a yeast starter and proper aeration be all that is necessary to get back to normal? Or, should I wait until next week for them to ship?

Answer 1

By creating the starter, you are allowing the yeast to feed and propagate to the levels you require for your batch. I've had NB send me smack packs with an ice pack, and it arrived cold as expected (this was roundabout the beginning of September, so still pretty warm here).

So, to answer your question more directly: Yes, you should be ok creating a starter (and it should propagate enough to give you enough viable cells). NB also typically ships packs that are well under the 2 month suggested shelf-life, though I've read and heard of people using packs that are over 10 months old and being fine after a starter.

Edit: I want to note that I mention the ages of the packs in comparison because by WYeast's own words (on their website) warm temps have exactly the same effect as long storage life.

Answer 2

Honestly, it's hard to say. As Akuta said in the other answer, yeast viability is decreased by increased temperature as well as age. Further, you don't know how old your yeast is until it arrives. Northern Brewer definitely SHOULD be moving enough yeast to send fresh stuff, but it doesn't require a lot of age to decrease viability.

Here's what I recommend: Use Jamil's Yeast Pitch Calculator (http://www.mrmalty.com) and calculate how much yeast you'll need for your beer, with a starter, including dates. (You should always do a starter, whether the yeast is fresh and arrived cold or not.) Tell the calculator that your yeast is a month old, even though NB's yeast will likely be fresher. That will help account for the reduction in viability you may experience due to heat. A great many homebrewers are surprised at how much yeast they really should be using, even though Wyeast and White Labs say on their packaging that their packages contain enough yeast for 5 gallons of wort. That's really dependent on the gravity of the wort, as well as the age and handling of the yeast.

Depending on the OG of your beer, I suspect you'll find that you may want to consider purchasing 2 packs/vials of yeast instead of just one. Jamil Zainasheff has done the yeast research and his pitch rate calculator is absolutely indispensable, and can help you account for things like temperature, somewhat, and age.