Old yeast - Toss or propigate?

Looking to brew my Breakfast Stout again, and I'm looking through the fridge and I find an old packet of Omega Yeast Labs British Ale II, packaged on 2/6/15.

The OG of the beer comes in around 1.084 and I generally try and put 6G in the fermenter.

Putting this through Mr Malty says I'd need to use 12 of the packets with a 2l starter, or 7 packets at about 5L of starter.

That's a ****ton of starter and yeast packets required. I know that the yeast is old, but is it really in this bad of a condition? Mr Malty doesn't seem to have an option to calculate for stepping up either.

I won't be brewing this for a week or two, so that's why I'm asking now - is this yeast just trash, or do I have enough time to build it up over the course of a couple of weeks? If so, how do I calculate this? Also, If I'm going to spend more in DME than I would spending another $16 on two yeast packets and making a starter that way, I will just toss it or save it for a lower OG beer.

Thanks for any advice!

The yeast will still be good to use. This starter calculator has a better handle on yeast viability.
http://www.brewunited.com/yeast_calculator.php

http://www.yeastcalculator.com/

http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

Both those calculators have steps in them. Brewersfriend also lets you change the pitch rate. Yeast Calculator lets you adjust the starting cell count which most calculators do not. This is important when considering companies like OYB and Gigayeast that put more cells in their pouches. Most of the calcs just go off the White Labs/Wyeast 100bil

I just ran 6 gal of 1.084 with that yeast on YeastCalc, 800ml stir plate then 1.6L stir plate gets you a bit of a cushion at 364 bil, your SG requires 344

Thanks for these links.

I had used Brewers Friend, but they reported the viability of this yeast packet to be 0%, which just didn't add up.

I wish there was some kind of consensus on the science of this. I know that Jamil Zainascheff states that he and Chris White worked on some yeast propogation and viability trends and he claims that while they both worked independently, they came up with similar results. It seems that every damn calculator I use I get different results with - Mr. Malty, Brewers Friend, Yeast Calc, and Beersmith all generally give different results for the same input factors.

Yea its a pain that they don't all really match up. I usually use Brewersfriend to get my cell numbers for the beer, since you can set different pitch rates. The 1 mil/ml was really set for pre brewers repitching. Pure (new) culture doesn't always require as much, that is where you get the .35m/L rates that the big labs say the 100 bil vial can do up to 1.06 with a very fresh vial and no starter. I tend to go somewhere between .5-1 for most of my beers. Bigger beers, like yours (or most Belgians, for example) I usually select the .75/L option from BF, then plug in the beer info on YeastCalc and play around until I get the cell counts needed.

Running that again with my method, .75/ml is spot on at 345 bil cells needed. At 1/ml it bumps up to 459, so you'd have to do another step up from what I posted above.

OR....its time to brew a lighter beer first with that yeast and then pitch the cake! Bonus, you get more beer.

When I use old yeast I make a .5l starter with about 1.025 wort. Let it run then consider that equal to a vial or pack of liquid yeast. I then run a calculator to determine my starter size. I like this calculator: http://www.yeastcalculator.com/