Sluggish Finish for Omega Voss

[NobleNewt]

This isn't my first issue with Voss not reaching expected FG, but it's under different circumstances. I started this thread about this time last year: Omega Voss Kveik: Should I Bottle?

This time, I brewed an AG version of Biermuncher's Ode to Arthur formulated for about 4.5 gallons. My OG was 1.046 which is what I expected and I mashed at 151 for 90 minutes. The mash finished at about 149, but I wasn't going to make the same mistake as I did in the above thread. Pitched a starter of re-used Voss Kveik (with nutrient), and it bubbled away like a champ. After about 48 hours, activity had slowed and my sticker thermometer was reading closer to room temperature than the 82* it did during most of the fermentation.

For kicks, I took a refractometer and gravity reading.. Both corroborated to 1.016... BeerSmith is expecting my FG to be around 1.007 which, in my experience thus far with Voss, is low even for a lower mash. Every refractometer reading I've taken since then has stayed almost identical at 6.5 Brix. (Yes, I know refractometers aren't the best way to judge FG, but it gives a good baseline for how fermentation is progressing.)

Since that reading, I've added the trusty heat pad, brought the sticker temp back up to the low 80s, and I'm seeing airlock activity again albeit slow. Added 1/2 tsp of Wyeast yeast nutrient and a tablespoon of fresh Voss slurry today.

I'm starting to think that the talk of kveik strains having trouble with low gravity wort are warranted. Anything else I can do to help this beer get the FG down besides giving it time and warmer temperatures?

 

[hottpeper13]

I've been finding a correlation between mash temps and ADF on the Voss and Hornindal. Lutra is on deck and will be treated the same way. I get between 78% and 83% ADF on most beers now. To achieve a low FG I do a step mash starting at 143* for 60 min then add boiling liquor to get to 158*- 160* for 30 min and I double the nutes in worts 1.060 and lower. I just finished a RIS that started at 1.102 and finished at 1.016, that's 84% ADF. Also it helps to start around 77* at pitch, wrap it up and let it go where it wants. When it starts to loose temp plug in the heater and set to 2*-4* above the highest it went. I check when my air locks go even and it's always done.

 

[NobleNewt]

I've been finding a correlation between mash temps and ADF on the Voss and Hornindal. Lutra is on deck and will be treated the same way. I get between 78% and 83% ADF on most beers now. To achieve a low FG I do a step mash starting at 143* for 60 min then add boiling liquor to get to 158*- 160* for 30 min and I double the nutes in worts 1.060 and lower. I just finished a RIS that started at 1.102 and finished at 1.016, that's 84% ADF. Also it helps to start around 77* at pitch, wrap it up and let it go where it wants. When it starts to loose temp plug in the heater and set to 2*-4* above the highest it went. I check when my air locks go even and it's always done.

That’s good advice. I don’t brew much of anything above 1.065, but I like Voss since I don’t have to baby it like most yeasts during the summer in Texas.

Most of my recipes, on a normal 152 single infusion BIAB, get down to 1.012 or 1.010.. Enough to get 75-78% attenuation most of the time and bottle.

This is the second time with a stout I’ve had this problem.... I also let the temp fall in both instances below Omega’s threshold. I took a gravity reading yesterday and it seemed to have dropped another point, so maybe some heat and more nutrient will at least get it down to 1.010 or so. I’d be plenty happy with that.

Next brew, I’ll try your suggestions. Thanks for the reply!

 

[NobleNewt]

I've been finding a correlation between mash temps and ADF on the Voss and Hornindal. Lutra is on deck and will be treated the same way. I get between 78% and 83% ADF on most beers now. To achieve a low FG I do a step mash starting at 143* for 60 min then add boiling liquor to get to 158*- 160* for 30 min and I double the nutes in worts 1.060 and lower. I just finished a RIS that started at 1.102 and finished at 1.016, that's 84% ADF. Also it helps to start around 77* at pitch, wrap it up and let it go where it wants. When it starts to loose temp plug in the heater and set to 2*-4* above the highest it went. I check when my air locks go even and it's always done.

Ok, a bit of a follow-up. I played around with the numbers on BeerSmith for a BIAB step mash as you described. I know what you're getting at: full beta-amylase conversion at 143*, full alpha-amylase at 158*. But when I create that profile in BeerSmith, it raises my FG by several points (like 6 in the recipe I was looking at). I trust your method, I just wonder why BeerSmith doesn't pick up on the additional conversion you get by doing both of those steps.

Just to see, I added a 152* step in the middle and it put my FG back down to where it was with a 152* single infusion. I'll try most anything to get rid of these sticky fermentations I've been getting with this yeast!

 

[hottpeper13]

I don't use a program just a calculator and pencil and the original back button,(eraser). Did i mention the eraser? Anyway, I believe it's a combo of the stepped mash and stepped fermentation that gets it down. I've not had good results trying to fix a stuck one and just live with it.

 

[NobleNewt]

I don't use a program just a calculator and pencil and the original back button,(eraser). Did i mention the eraser? Anyway, I believe it's a combo of the stepped mash and stepped fermentation that gets it down. I've not had good results trying to fix a stuck one and just live with it.

Haha! Good enough. I think I got the fermentation to kick back up. My refractometer is reading about 6.2 Brix, down from 6.5. From an 11.5 Brix OG, that would put me at around 1.011. I'll likely give it the week at elevated temperatures to see if it'll drop another couple of points before I take another hydrometer reading. I hate taking so many hydrometer readings because of how much beer I lose to samples!

 

[NobleNewt]

I've been finding a correlation between mash temps and ADF on the Voss and Hornindal. Lutra is on deck and will be treated the same way. I get between 78% and 83% ADF on most beers now. To achieve a low FG I do a step mash starting at 143* for 60 min then add boiling liquor to get to 158*- 160* for 30 min and I double the nutes in worts 1.060 and lower. I just finished a RIS that started at 1.102 and finished at 1.016, that's 84% ADF. Also it helps to start around 77* at pitch, wrap it up and let it go where it wants. When it starts to loose temp plug in the heater and set to 2*-4* above the highest it went. I check when my air locks go even and it's always done.

Thought I'd offer a bit of a follow-up on this. I brewed an Amber ale cloned after Saint Arnold's in Houston. Used a similar step mash as you described, but instead opted for 40 min. @ 143, 20 min. at 152, and 30 min. at 158 before mashing out (BIAB) at 168. Also kept my fermenter around 90 degrees this time with the help of an InkBird and a seedling mat, and I'm happy to report at close to 48 hours from pitching, I'm nearly down to terminal gravity. Currently sitting at 1.013, where BeerSmith is expecting something in the 1.011 range.

I should also mention that I opted to use the Lallemand Voss this time which took off like a rocket and required a blow-off. Granted, my troubles had been with the Omega Voss, but I figured the isolates are at least similar enough that I could give it a try. Also doubled the nutrient as you recommended. My OG was 1.057.

I think I'll stick with a step mash moving forward to get my attenuation up and gravities down as much as possible. The sample I tasted while taking my hydro reading was well-balanced in terms of body, and I don't feel like said body was affected much if at all by using a step mash. Anyway. I may end up trying the Omega Voss again in the future, but the Lallemand performed admirably enough that I'm likely to go with it moving forward.