Vigorous fermentation, no change in gravity

[FrankCazabon]

Hi, I tried out Oslo kveik from bootleg biology for the first time this weekend. Had got a small sample of the dried yeast from nano con last November. Made a starter about 36 hours before pitching. Pitched at 26°C and apparently had a vigorous fermentation (lots of gas produced and lots of Krausen) which seemed to stop about 36 hours later. However the reading in my refractometer is 1.036 SG which is really close to my OG of 1.038.

Unfortunately I broke my hydrometer so can't double check the reading but I had calibrated the refractometer just before.

I've ordered a hydrometer but it won't be here for another week.

I don't taste any alcohol just a kind of orange to go along with the centennial and cascade hops.

Can anybody help explain this? Could I have an apparent fermentation without reducing the sugar content? Or is it just that my refractometer is not working properly (it did give me slightly off readings on a previous brew a week ago which is why I calibrated it).

 

[myndflyte]

Refractometers will give wrong readings when checking gravity with alcohol present. Make sure you use the calculator that says "With alcohol present" Refractometer Calculator - Brewer's Friend

 

[FrankCazabon]

Yes, thanks, but the reading had hardly changed so the refractometer calculations only show 0.3% alcohol by volume.

 

[VikeMan]

How sure are you of your OG reading? Was this an extract batch topped off with water?

 

[FrankCazabon]

No, all grain, full mash. Been brewing for 20 years. The OG was a little below what I expected but I've begun to doubt the refractometer so I'm not 100% certain

 

[TheMadKing]

How sure are you of your OG reading? Was this an extract batch topped off with water?

Are you thinking stratification? My first thought as well

OP, did you use a high percentage of oats or wheat? I've seen a protein barrier cause a beer to ferment up high but not much at all below the protein layer.

If your OG was 1.038 you shouldn't be able to taste any alcohol. Usually you can't actually perceive ethanol until 5-6%. Also if you produced CO2, the only place it could have come from was the disassembly of sugar molecules, so fermentation DID occur. If that's the case then the issue is likely with your refractometer reading, or with a differential fermentation

 

[FrankCazabon]

I had not thought of stratification (I guess you mean different layers getting fermented at different rates). No oats or wheat. 2 row, carapils, caramel malt and goldpils Vienna. 4th time I'm doing this beer and decided to try it with the kveik to see the taste difference. ABV should be about 5%.

Hopefully it is just the refractometer but just last week it worked ok, even if the readings appeared slightly off. I'll refrigerate the beer until the hydrometer arrives and see what readings I get then.

 

[Vale71]

I once had fermentation start off so vigourously that the yeast never got to the bottom of my conical fermenter. The sample from the sample port, which is located above the cone, was already well attenuated but when I slowly opened the dump port thinking I could start damping trub what came out was basically unfermented wort. Some top-cropping yeast can apparently literally stay on top so much that only part of the wort will ferment initially. Of course the yeast started dropping eventually and in the end the whole fermenter had fully attenuated beer in it.
What type of fermenter are you using and where are you pulling the sample from? Could you try and pull a sample as close as possible to the surface?

 

[FrankCazabon]

I've actually taken from both top and bottom. It's just a plastic bucket with an outlet near the bottom of the bucket.

 

[TheMadKing]

ABV should be about 5%.

The only way to get to 5% ABV with a 1.038 OG is to ferment down to 1.000 FG which is 100% apparent attenuation, which seems very very unlikely given the grain bill you mentioned, unless you are using glucoamylase enzyme in your process. So either your OG was higher 1.038 (another point in favor of a faulty refractometer), or you might have mis-estimated your ABV.

 

[FrankCazabon]

Yep, that's why I started suspecting the refractometer needed calibration. Normally this brew starts at 1.043/1.045 and gets down to about 1.004. This is the first time I calibrated it so I'm wondering if I've done something wrong. I made my own distilled water and adjusted the reading so that it was 1.000

 

[TheMadKing]

Yep, that's why I started suspecting the refractometer needed calibration. Normally this brew starts at 1.043/1.045 and gets down to about 1.004. This is the first time I calibrated it so I'm wondering if I've done something wrong. I made my own distilled water and adjusted the reading so that it was 1.000

You accounted for temperature when you calibrated it I assume?

 

[FrankCazabon]

the water was at room temperature which is about 27C where I live. Would that have affected it?

 

[TheMadKing]

the water was at room temperature which is about 27C where I live. Would that have affected it?

I would be very surprised if it affected it THAT much - though if you did it in a really hot room (over 35C), the amount of liquid on the slide is so thin it only takes about 1-2 minutes for it to equilibrate to the temperature of the room you're in (or the temperature of the refractometer more specifically)

 

[Vale71]

the water was at room temperature which is about 27C where I live. Would that have affected it?

Yes but in the order of less than a 1000th which is surely way too small for your refractometer to even detect.

 

[FrankCazabon]

I got a replacement hydrometer and took a reading and got 1.035, so my refractometer seems to be OK. As far as the beer goes, I'm totally confused. I am currently racking it off that yeast and into another fermenter and going to add some other yeast. Hopefully I'll at least get something drinkable from this.
Thanks for all the input.

 

[TheMadKing]

I got a replacement hydrometer and took a reading and got 1.035, so my refractometer seems to be OK. As far as the beer goes, I'm totally confused. I am currently racking it off that yeast and into another fermenter and going to add some other yeast. Hopefully I'll at least get something drinkable from this.
Thanks for all the input.

That's totally bizarre.. Are you sure you had Krausen and lots of CO2?

 

[FrankCazabon]

Yup, I didn't take a picture of it but yes and there were lots of bubbles coming out. I've attached a picture of the ring fitness around the top of the bucket after I transferred to another one.

 

[TheMadKing]

Yup, I didn't take a picture of it but yes and there were lots of bubbles coming out. I've attached a picture of the ring fitness around the top of the bucket after I transferred to another one.

That's pretty strange, definitely looks like a normal Krausen line to me.

 

[FrankCazabon]

Definitely one of the strangest things I've seen in my history of brewing.