Yes. A starter roughly doubles the cell count, some variation given the size of the starter. A couple of things might have happened, the first of which was underpitching. Double 100 x 10^6 cells and you have enough for 200 ml of wort at the standard lager pitch rate of a million cells per milliliter. A second possibility is that when you harvested your cells, you left the least flocculant behind. They're the ones that "finish" the beer when the other cells have dropped out. I'd lean toward that because it looks like the early part of your fermentation went well.

 

I have seen that happen to me on occasion and I can't say with any certainty why it happens. It could be caused in the mash without you knowing it. This accelerated method seems to work pretty good. When I brew a lager I leave it colder longer than 3 days, it's more like 6-7 days and then I bring the temp up slowly to @ 65F. I don't watch the gravity at all until I cold crash it. So it stays at 65 for 5-10 days. Maybe it needs more time, who knows?

How long did the extra cells set in the refrigerator before the second starter was made? How big was the starter? The answer to the question may give a clue as what happened, but I think it would have to be a severe under-pitch for this to be a problem. As long as the wort was aerated with pure oxygen, the yeast can handle an under-pitch. This seems more like the yeast was stressed a bit, but from what it's hard to say.

If you taste the beer and it's doesn't taste sweet, phenolic, fruity or has a lot of sulphur, then the answer is likely in the mash. The mash can add some sweetness, but most sweetness comes from the yeast depending on the strain.

As long as the beer tastes good, then don't worry about, you shouldn't fret too much over a beer that didn't attenuate like you planned. Make note of it and if it happens again try to see if there are any similarities to might give you a clue as to why this happened. I don't get super attenuation with lager yeast, 76% is the upper limit most times. I had a Dunkel finished at 1.018 and it wasn't sweet, so the numbers don't always matter.

Hope that helps.

 

I also lean towards mash temp as well. Are you sure those were exactly the same? If your second got mashed higher or maintained temp during the mash better that could explain it.

 

Many years ago, I was hosting Jamil and Chris White at an event. In all of our conversations it always came back to a statement from them, " It's all about the Yeast!" I think it was Jamil that actually said it, but there was beer involved and the waters may have been a bit muddy.
Take it to heart!
Cheers,
Brian

 

Since the repitch is the major variable changed, I tend to agree with Brian ^^^^.

 

Was the second batch actually finished? I use 2206 fairly regularly and it sometimes gets a little lazy munching away the last few points.
Do you use aeration / oxygenation ?

 

Do you mean 100 billion? 100x10^9? A native English speaker, I read that 100M as 100x10^6, about enough to pitch 100 - 200 ml of wort, a serious underpitch.

 

I'm also a German speaker, where 100 M would be 100 Milliarde, or 100x10^9, a billion in English. Our notation is not universal, that's why I asked. Also because it would be a cause of underattenuation woes to use that little yeast in a full-size batch. Just curious: How did you know how many cells were in your krauesen?