Very low FG... is this even possible? possible refractometer issue.

I am stunned. I just bought a new refractometer and started taking gravity readings of my beer in the primaries. I am shocked and a little confused about what I found.

Last weekend I brewed an IPA using 12lb of 2 row, 1lb crystal 60, and Nottingham yeast for 5.5 gal. I hit about 62% efficiency which is what I expected measuring with my junk hydrometer, 1.058. Today, I took a reading with my refractometer Which I calibrated and checked, and it said 6 brix. WHAT!!!! 1.003? In a week, with Nottingham? Is this even possible? My hydrometer claims 1.010 which is still pretty crazy considering that my FG estimate is 1.014. Can someone tell me what is going on? I took my refractometer sample from the very top of the fermenter (twice) and floated the hydrometer in the bucket to get the readings. Is it possible that the beer at the top of the bucket is very light and there higher gravity at the bottom?

-J

dont you have to take the OG reading with the refractometer and use that to determine your current gravity???

I remember hearing that you have to use the OG taken with the refractometer in some equation. Take a hydrometer reading and see what it says.

Edit: just noticed you already took a hydrometer. I dont know. I've used Nottingham 2 times and both beers finished at 1.010 after 3 weeks in the primary

Refractometers cannot be used (without applying some adjustments, which I believe are available in BeerSmith and ProMash) for beer after it has fermented. The numbers simply are not right.

Yep, I used the calibration equations in Beersmith using my OG numbers that I took with my hydrometer last week. I'm sure the hydrometer isn't 100% perfect, but it's not that far off.
-J

I did a batch a in October that went from 1.074 to 1.010 in one week with Yellow Nottingham. I was letting it run hottish 74°F plus looking for extra flavor.

I used the same equipment to measure both sgs. I don't know if it is _exactly_ right but I do know there is a truckload of alcohol in that ale.

See post 6 here:

https://www.homebrewtalk.com/showthread.php?t=40361

I dont _know_ it, but I suspect I would have found an sg <1.020 starting about day four.

1.010 is entirely reasonable if the target was 1.014.

The beer stays well mixed throughout the ferment.

[By the way, 6 Brix is about 1.024]

david_42 said:

1.010 is entirely reasonable if the target was 1.014.

The beer stays well mixed throughout the ferment.

[By the way, 6 Brix is about 1.024]

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Beersmith calculation says with OG 1.058 and 6 brix after fermentation begins equates to 1.003. Am I wrong? This could very well be an issue with not using the same equipment to read gravity throughout the process. I should get better results with my next beer as I will be using the refractometer from start to finish.
-J

miatawnt2b said:

Beersmith calculation says with OG 1.058 and 6 brix after fermentation begins equates to 1.003. Am I wrong? This could very well be an issue with not using the same equipment to read gravity throughout the process. I should get better results with my next beer as I will be using the refractometer from start to finish.
-J

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Good luck with it. Based on my past experiences with it, I think the formulas are still worthless. I used a hydrometer and refractometer side-by-side on a couple of batches for measuring BOTH the OG and FG, and using beersmith's during-fermentation refractometer calculator, the calculated FG from the refractometer reading was way off from the reading with the hydrometer of the same wort. I get the feeling that there are too many variables that the refractometer calculators don't take into account.

You can trust hydrometer readings, but you can't necessarily trust refractometer readings. If your refractometer reading isn't agreeing with your hydrometer reading, then either A) you messed up one of the readings, or B) the calculator is worthless. Since the FG readings given by the calculator from the refractometer readings NEVER agreed with hydrometer readings for me, I no longer trust the calculator.

thanks for your help folks. I elected to rack to a keg and crash cool to keep it from fermenting out further.

-J

Do NOT underestimate the power of Nottingham! That's 11.5 grams of dry yeast. I'm pretty sure you'd get your arm fermented off if you stuck it in the primary....

when i've compared calculated FGs from my refracto and real FGs from my hydro they're usually within 3-4 points. thats ok by me. the only reason i take gravity readings of fermented wort is so i can see that it's finished fermenting, and then i'm only checking for movement. using the calcs in beersmith are just fine for seeing that it's close, and it's all relative anyway. who cares if my refracto says the SG is 9 and my hydro says its 13. if it's 9 for 3 days in a row its done, isn't it? done is done. i always take a hydro reading before bottling/kegging and that's the number i use to calc my ABV%. also, i've measured distilled water at 60F with my hydro: 1.004. that sort of inaccuracy accounts for your strange reading, at least a little bit. the ability to drop .25ml of wort onto an eye piece for a near instant SG reading far out weighs the hassle of not having spot on readings when there is alcohol in solution, IMHO.

I agree, that a refractometer is still useful for monitoring changes in SG so you can monitor for the end of fermentation. But I have a hydrometer thief - since I use carboys it takes about the same mount of effort to pull a small sample for a refractometer as it does to dunk the thief and get a hydrometer sample, which can be returned immediately so it's no more wasteful. Since that makes each method about equally convenient, I choose to stick to the more accurate one. If I didn't have the thief, I'd stick with the refractometer for this, so to each his own.

I still find the refractometer very useful for all-grain brewing, you can take instant readings of mash/sparge runoff and the like - but that and taking OG readings is about all I do with it anymore.

Funkenjaeger said:

I still find the refractometer very useful for all-grain brewing, you can take instant readings of mash/sparge runoff and the like - but that and taking OG readings is about all I do with it anymore.

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It's about all I use it for also, but I do find it handy when doing the mash.