Dunkel Ferment - stalled or not?

[DCUSA]

I don't have a ton of lager experience-- this is my 4th lager and 2nd dunkel. My first dunkel definitely stalled out at .019, but as my very first lager with the mistake of a small 1L starter or none at all, I can't remember.

This time I made a 3L starter on a stirplate and it was very active for 48 hours before crashing and decanting for pitch.

82% Weyermann 7L munich
9% Melanoidin
4.5% Weyermann Caramunich 51L
1.5% Carafa

WLP 838 Souther German Lager

148 mash for 80 minutes, but I only hit .042 OG because my efficiency can be crappy. Depressed about that fact, I boiled 9 oz light DME and boiled it / pitched it into the fermenter just after high krausen to add about 5 points.

Per White Labs lager instructions, I pitched the decanted starter at 65F and waited for activity to ramp up. Then I dropped the temp to about 57 on day 1, and then to 50 on day 2 and let it rip, which it did for a couple days. On day 4, with gravity at .020 and krausen dropping out I pulled the fermenter from the keezer and let it rise naturally to the ambient temp of 63-65.

Now I'm at end of day 5, and it's still at .020. Plenty of co2 bubbles are visible rising from the bottom, but not enough to show very much on the airlock. Still at 65F. At this point I'm wondering what is a realistic FG target to achieve in the next week's rest at 65? .014? 0.018? I imagine there's a couple points left, but being so inexperienced with lagers, I don't know what to expect.

 

[VikeMan]

Your grain bill percentages only add up to 97%, but I'll assume the proportions are right.
With your grain bill, mash temp, and mash length, plus the 9 ounces DME added later, for a total effective OG of 1.047 in 5 gallons of wort...
I'd expect this to get down to about 1.012.

 

[DCUSA]

Thanks-- the remaining 3% was acidulated.

Still sitting at .020 the next morning. 65F. I haven't timed it but I think a small bubble works out of the airlock every 5-10 minutes. I'll give it a few more days. My gravity is being measured by a tilt.

 

[VikeMan]

I don't own a Tilt, but I have read many posts about them not necessarily being accurate during fermentation. Also, day 5 can be considered fairly early in many lager fermentations.

 

[DCUSA]

Yeah, I take the tilt with a grain of salt but use it to look for a downward trend over time, and for a stable FG. And more importantly temp. I've used it for about 15 ales and a couple lagers including this one. I don't pay much attention to the pre-FG readings because I've never had an ale stall out in my life.

I've done 2 successful lagers in the past-- a helles and a pils. I was surprised how both of them hit FG within 5-7 days just like ales.

Reached a .019 on the middle of day 6 (today). If it can average a point per two days, .012-.014 FG would line up with a sensible timeframe. Just not used to it I guess.

 

[DCUSA]

It's day 9 and I'm still stuck at .019, at 67F. Confirmed the tilt reading with a floating hydrometer. I pitched a couple packets of old WLP kolsch and czech lager yeasts that were 5-6 months past recommended viability to see if they could work on a few more points. Seems like no.

I am wondering if I did not manage my mash temp evenly, and with a high % of darker base malt like Munich 6-10L, am I simply out of fermentable sugar? The starter was huge and active, and the first couple days of ferment were roaring.

Last ditch effort could be to krausen the belgian strong I brewed yesterday, and pitch a cup of it. Style be damned, I'm desperate to get this thing attenuated enough to consume! And honestly could be an interesting flavor profile if the trappist yeast can do anything to it.