lager yeast starter

[trvlnpt34]

I got a free vial of WLP833 German Bock yeast from the LHBS because its best by date was May 2012. I did a 2L yeast starter and it did ferment some. So then after doing a little research I decided to add basically another 0.5L of wort and let it keep going for a few days. So it's been 6 days and I plan on brewing a Munich Dunkel with it tomorrow. I put it in the fridge this morning to drop all the yeast out but it is still pretty cloudy, and the layer of yeast on the bottom is about 1/2 nice white looking yeast and 1/2 darker probably dead yeast. My question is, should I still use it for my Dunkel tomorrow?

I have a vial of WLP820 as well that is fresh. Would it be worthwhile to add it along with the 833? Or should I just use the 820 instead (problem is I don't have time to do a starter with it)?

I'm still pretty new to doing starters so my process for this might be screwed up anyways. Any help is much appreciated!

[spiderwrangler]

What temp are you fermenting at? If at lager temps, you are going to want a fair bit of yeast, the vial you've stepped up, and the additional vial may not be enough.

[trvlnpt34]

I'll be fermenting in the mid 50s which is pretty much what temp my basement stays at.

[spiderwrangler]

According to the Mr. Malty calc, you would need about 380 billion cells. A pack that old it puts at 10% viability, or around 10 billion cells. Not quite sure on scaling up for the growth you got, but I generally figure if I'm putting 100b in a 2L starter, I'll get back close to 200b (on stirplate). For 10b in 2L, you'll probably get more than just a doubling like that, but even if you figure you get 4X growth, that puts you at 40b. Your additional 0.5L starter say gets you an additional 10b. Now you are at 50b... even if you add the other vial, you will only be at 150b, and I feel that is likely an over estimate. If you were to do another series of yeast starters, you would be able to get your numbers back up, perhaps a rinse and pitch your propped up one into a fresh 2L once or even twice, but you'd likely want to do a larger volume starter to build an even bigger pitch.

While my numbers are somewhat conjecture, I do feel confident in saying as is, you will be underpitching, even with the addition of the second vial.

[trvlnpt34]

Good info, thanks.

What are your thoughts on combining 833 with 820? I just recently used that American Ale yeast blend (060) with a Vanilla Porter and it turned out pretty good. But I've never actually combined yeasts before.

[Mills]

Good info, thanks.

What are your thoughts on combining 833 with 820? I just recently used that American Ale yeast blend (060) with a Vanilla Porter and it turned out pretty good. But I've never actually combined yeasts before.

Nothing wrong with combining yeast strains, especially in this instance as they are both similar. Chances are is that the strongest most viable yeast will create the most dominant flavor and aroma compounds.

Mills

[spiderwrangler]

Yes, combining most yeast strains will be fine, but I still think it will be a low pitch rate for your beer (I'm assuming ~1.052, 5 gal).

[trvlnpt34]

This is the yeast cake from that combo of 833 and 820 that I used in my Munich Dunkel. I would like to use it for a Maibock next, but I'm a little leary about it because it looks so dark. I'm not sure if that's from the Dunkel color or if the yeast is unhealthy. The Dunkel did ferment pretty good, though my gravity was not quite as low as I was hoping for.

I thought the good yeast should look much more white but I'm new to yeast washing and reusing it, so I'm really not sure if I'm just being paranoid or not.

Any thoughts?