Alcohol Correction of Refractometer Readings

I have this Hef I'm working on, started at 11.2 bx, or 1.045. Now, two weeks later, I'm getting ready to bottle on Monday, so I check the brix with my refractometer, do the conversion, and get 7.6 brix, or 1.028.

I thought "uh oh." I started doing some research about fixing a stuck fermentation, and settled on stirring up the yeast and aerating. That's what it said. It made me a little nervous because I know you want to prevent oxidation, but OK. So I hooked up my aerator and continued my research.

First thing I did was dig out my old hydrometer that I hadn't used in 10 years. I got a reading of 1.016, and that's when it hit me -- the alcohol has to be accounted for, because it changes the refractory index of the liquid. Turns out, my corrected conversion of 7.6 brix is 1.018. So I shut off the aerator, prayed I didn't infect the wort, and made the corrections for a couple other batches I have on the line.

I used the refractometer calculator at Brewer's Friend, so I assume it's right. I know it turns out a little weak, at 3.6%, but I plan to call it a Session Hef, and pour two at a time.

Anyway, I hope the aeration doesn't ruin the Hef.

You might want to look at the refractometer correction calculator here: http://seanterrill.com/2012/01/06/refractometer-calculator/ Sean did a lot of correlations between reftacts and hydrometers to develop new correction curves.

Brew on

Rousing the yeast is a good idea when you really have a stuck fermentation (sounds like you didn't after all), but aerating after the first couple days is not something I'd ever recommend. Drink it quick because it is going to start showing signs of oxidation.

+1 for Sean Terrill's calculator

@doug thanks for the link; I like that refractometer calculator.

@mbb that's what I was worried about. I'll bottle it today and we'll get it down ASAP.

Oh, dear. I'm afraid my Hefe is going to need professional help. I bottled it six days ago and opened one today to test the carb level, make sure it was working. It does not taste good. I haven't educated my palate enough to peg the issue, so I'm going to ask a friend of mine who's a pro brewmaster. It has some off flavor, like bad yeast or something. I did have trouble pitching -- I used some liquid yeast that had died from heat in shipping, so I repitched after 48 hours. I wonder if the dead yeast is the culprit.

Will a conditioning period improve it, you think?

MannyEdwards said:

Oh, dear. I'm afraid my Hefe is going to need professional help. I bottled it six days ago and opened one today to test the carb level, make sure it was working. It does not taste good. I haven't educated my palate enough to peg the issue, so I'm going to ask a friend of mine who's a pro brewmaster. It has some off flavor, like bad yeast or something. I did have trouble pitching -- I used some liquid yeast that had died from heat in shipping, so I repitched after 48 hours. I wonder if the dead yeast is the culprit.

Will a conditioning period improve it, you think?

Click to expand...

No. If you aerated it after it started fermenting, it is oxidation that is ruining the flavor. It should get much worse with time although it could be an infection as well it needed to be repitched at 48 hours.

Bummer. It'll be sad to pour it all out, but it'd be worse to actually drink it. Maybe I'll save some for people who don't return bottles.

Oxidation (which you're almost certainly going to suffer from) does a few things. It will make the beer become a bit darker, it will significantly mute the malt character, and it will develop a wet cardboard / musty aroma and flavor. Time will only make it worse. If it's undrinkable now, dump it and save yourself the continued headache.

I found a way to save my Hef. It's a little weak, and there is a very mild bit of oxidation, but I made a sort of shandy with it by mixing up a citrusy energy drink of my own design. It has about half the sugar of a Red Bull, and I prefer a shandy that isn't too sweet, or it doesn't quench my thirst. It's a really nice blend, like not just a tolerable workaround, but refreshing and very drinkable. It has been a hit with the friends and family. Makes me thirsty just writing this.