I’ve made a CAP twice recently and both times the ferment takes about 6 weeks to reach terminal gravity.
The grist is 75% american 2 row and 25% flaked corn.
OG is approx. 1.06
Both times I’ve used WLP800, 2L starter stepped up to a 4L starter.
I cool the wort down to around 65 degrees, transfer to a carboy and put in the 'fridge to cool down to pitching temp (I put the 4L starter in the fridge along with the wort so its the same temp as the wort when I pitch)
I rack the cooled wort off the trub, add pure O2 for 1-2 minutes, decant starter, pitch yeast.
I leave the temp control set at 50 degrees.
After two weeks it will be around 1.04 and takes the next four weeks to reach 1.015.
What I’ve ended up doing is at the three week mark raising the temp to 60 degrees and leaving it there until I reach the 1.015.
I’m wondering if the percentage of flaked corn is resulting in the yeast not having enough nutrient.
I add DAP to the starter and Servomyces to the wort.
Should I be adding more nutrients to the wort prior to pitching?
Would it help to add, say Fermaid-K, at the 2 week mark?
Suggestions?
Only thoughts are to cool the wort and starter to 45F, pitch and then warm to 52F for primary. Sounds like you have enough of yeast. What about your temp controller? Could it be off and it’s too cold?
All else sounds good to me.
Dave
Whats your mash temp?
Yeah, something is off here. A lager of that gravity should reach FG in two weeks, tops.
My last CAP was done with the D-rest in a little less than 6 days. If it is taking weeks, you have lost yeast viability, or you need some nutrients, or not enough O2, or you yeast count is low. I do add zinc for the yeast.
How are you preparing your 2L or 4L starters? How much DME or sugar is going into those starters?
I don’t make many batches of lager, 2-3 out of 15-20 batches per year,
Anyway, I don’t have any issues with ale fermentations and I’ve not had this issue with other lagers, only with the two batches of CAP.
My starter receipe is 1/2 lb DME, 2L water, 1/8 tsp DAP, stirplate for a couple of days, same for all my starters.
2 minutes of pure O2 seems like it should be enough.
For my ales I just use a Servomyces cap per batch and I have done the same for these.
Wondering if the 25% flaked corn is resulting in a wort with to little FAN?
Jeff, how much nutrient do you use in the wort prior to pitching?
I use the zinc in the wort, half a 15 mg diet supplement tablet is in the recommended range for 10 gallons.
The starters get a little nutrient, I use one of the blends, i think the bag says LD Carlson. These have vitamins, minerals and FAN. DAP is a good source of Nitrogen so you have that covered. You might think about what other things the yeast need. From a couple of presentations at the NHC, I picked up the fact that the one thing wort lacks is zinc, so that is why I add it. Trace levels of copper are good too, but there is some copper in my mash tun, boil kettle, and the imersion chiller so I don’t add any additional copper. If you don’t have any copper in your system, a length of copper pipe in the boil would give you trace amounts.
Jeff, since you’ve started using the zinc, have you noticed any difference? I use the Wyeast nutrient blend which contains zinc but sometimes I forget to add it (last Saturday) and I’ve never had an issue with Sluggish fermentation because of it. I did a Helles a few weeks ago and it was done in 10 days at 48-50 degrees.
Everything you’re doing for this CAP seems spot on. I think the long fermentation time you’ve experienced might have more to do with the yeast being 1st generation, than the 25% adjuncts you added, because the Servomyces you added should have been enough nutrients.
I know of a couple breweries in my area that in addition to yeast nutrients use zinc additions in the boil kettle. I don’t doubt it helps the yeast, however, I haven’t tasted a difference in their beer since they began using it.
My lagers used to take 2 weeks for the primary. If they are not down to where it is time for the D-rest in 4 or 5 days I start to get worried ( a day or 2 longer for a 1.080 doppelbock). I have now also been pitching the yeast amount that mrmalty calls for, O2, and temperature control. The zinc helps, but I think you need to do all of those things to get a quick and clean fermentation. Well, all of that and talk nice to the yeast and show it the respect it deserves for doing all of the work at cold temps. ;D
Yep… I knew I was missing something ;D
4-5days wow!
I brewer lagers, and high gravity bocks quite often, and use many differnt lager yeast strains and have never been able to shorten the legth of primary fermentation time under 2 weeks. However, I do tend to ferment my lagers quite low around 45F.
Im interested to know if you’ve noticed any difference in flavor from the new method that results in faster fermentation times and the older method that took two weeks to ferment out?
Lagers are really no different from ales in that the majority of the flavor compounds that are going to be produced occur during the lag phase. Once fermentation is under way temperature changes have much less of an impact. Once they reach >50% attenuation (which takes about 5-10 days, depending on gravity) I’ll ramp all my lagers up to 20°C. This is SOP in the pro brewing world; I assume it isn’t as common among home brewers just because precision temperature control is less common.
Interesting. I always thought one of the reasons why many craft brewers choose to brew ales over lagers is becasue lagers take much longer to ferment. Thus, holding up a fermentaion tank that could potentialy produce an ale in less time. Which can in return mean more profit in less time.
IME, it isn’t the fermentation (though it does take longer) so much as the conditioning time. An average-gravity lager will be finished with fermentation and warm maturation after maybe 7-10 days, but it isn’t going to taste “right” without a couple weeks of lagering.
That makes sense. Thanks for the clarification.
Thanks for the feedback and suggestions.
As far as copper goes, I think my IC probably takes care of that.
I have read in the Jamil Z/Chris White book about the relative slowness of first gen yeast. Maybe I’ll harvest some of the yeast from the current batch and make another CAP just to see what impact that might have.
Also, from the Jamil Z/Chris W book on yeast, I did figure out that I might have under pitched by 20% from the recommended level.
I guess the take away for me is more/better yeast and some additional nutrients.