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Trauts · 08-21-2012, 08:19 PM

here goes:

I just brewed my first batch of alcoholic ginger beer. It turned out all right. I'm making a number of tweaks for the second round, and now that I'm more informed, am actually going to measure OG/FG so I can figure out my ABV. (I'm also going to be adding significantly more sugar to try and hit ~13% ABV.)

When I looked at the cost to get what I'd need to use a hydrometer (a wine thief, hydrometer and hydrometer test tube) and how together they were going to cost ~$25 and be a pain to use, I figured I'd drop about $35 on amazon and get a cheap refractometer instead.

My questions: do I need to do corrections any differently because I'm making ginger beer instead of beer beer? In particular, do I need to change the "wort correction factor": http://seanterrill.com/2012/01/06/refractometer-calculator/

(If you aren't familiar with ginger beer, it's basically water, sugar, ginger, lemons, and yeast.)

Edit: I found an explanation of the wort correction factor on the wiki, and it sounds like in order to use a refractometer, I'm going to need a hydrometer anyway for calibration purposes. Is this a correct observation? Is there any way around this?

**chickypad** · 08-21-2012, 09:03 PM

Quote:

Originally Posted by Trauts

Edit: I found an explanation of the wort correction factor on the wiki, and it sounds like in order to use a refractometer, I'm going to need a hydrometer anyway for calibration purposes. Is this a correct observation? Is there any way around this?

I like my refractometer a lot, but I find that the correction for fermented wort is close but not perfect (especially at extremes of SG). I always use the hydrometer for final reading.
I think you can do better than $25. Hydrometers at my LHBS are $6, and $4 for the plastic cylinder, although I see folks on here using the plastic tube it comes in with no extra cost. You can use a sterilized turkey baster for sampling.

rhamilton · 08-21-2012, 09:14 PM

The refractometer is only useful for measuring OG. Even with 'correction factors', I found that my measurements can be significantly incorrect in the range of .02 points or higher (yes, even after correction).

Like chickypad recommended, always verify your FG with a hydrometer.

Trauts · 08-21-2012, 10:02 PM

Hrm, that's disappointing. I'm only brewing 2 gallons at a time, so there's not a lot of extra and putting it back in isn't something I'm thrilled about. Not to mention it has to be a pain to sanitize all the pieces.

I'm not sure knowing the ABV is important enough to me to justify the expense or the time to sanitize/measure/read temperature. What kind of margin of error would I be looking at if I just looked at a brix vs potential alcohol table?

According to http://winemaking.jackkeller.net/strains.asp , the yeast I'm using (Red Star Montrachet) says it stops producing alcohol reliably at 13% ABV.

If I put in a minimum of 2lb 4oz sugar (per gallon), is it safe to say I'll get ~13% when it 'stops fermenting' (based on airlock bubbling), even if I put in more sugar to make it sweet?

a10t2 · 08-21-2012, 10:04 PM

If you're fermenting only simple sugars, then you wouldn't need a correction factor, and you'd want to use an FG correlation intended for wine, not beer.

**TopherM** · 08-22-2012, 05:17 PM

If you make a 13% beer with a yeast that is rated to 13% max, you are going to have problems carbonating, unless you happen to keg.

The yeast start to zonk out (<-- scientific term), and will not carb or clean up your beer. You need to go pick up a packet of yeast that is rated above 13% (high gravity belgian, wine yeast, etc.), make a slurry, and add a few drops from an eye dropper to each bottle.

Good luck!

Trauts · 08-23-2012, 05:28 AM

Quote:

Originally Posted by TopherM

If you make a 13% beer with a yeast that is rated to 13% max, you are going to have problems carbonating, unless you happen to keg.

The yeast start to zonk out (<-- scientific term), and will not carb or clean up your beer. You need to go pick up a packet of yeast that is rated above 13% (high gravity belgian, wine yeast, etc.), make a slurry, and add a few drops from an eye dropper to each bottle.

Good luck!

Thanks Topher! What do I do to prevent that new yeast from taking over and eating up the extra sugar meant for sweetening? (other than using non-fermentable sugars)