Gravity Readings

Refractometer vs hydrometer

What are some advantages and disadvantages? I do not care about cost at this point because I accidentally just crushed another hydrometer in my fingers yesterday.

with a refractometer you have to do math to get the SG and other readings in addition to adjusting for temp. on the other hand the refractometer uses a much smaller sample than a hydrometer. other than that i cant any real advantage of one over the other.

Refractometers are also only really useful during the boil.

Is it a fair assumption that they are much more durable?

*dbl post*

Gremlyn1 said:

Refractometers are also only really useful during the boil.

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Not really true, it is no longer a common recommendation to do boils for mead and this is straight from Hightest's mead FAQs and pdf's http://home.comcast.net/~mzapx1/FAQ/Refractometer.pdf
I believe he uses refractometers exclusively allowing him to take many more readings to more accurately track a fermentation without having to worry about taking too much out for hydrometer samples

bubbachunk said:

Refractometer vs hydrometer

What are some advantages and disadvantages? I do not care about cost at this point because I accidentally just crushed another hydrometer in my fingers yesterday.

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I think you are a perfect candidate for a refractomer. If you can navigate HBT on the cpu then you can manage any of the available free spreadsheets used to convert brix to sg etc.

You can use them to see how ripe fruits are. I have no problem using a hydrometer for brewing, myself.

They are more durable in that I don't see a person crushing one with their fingers. I wouldn't drop one though. But then, I've never broken a hydrometer with my fingers. Maybe you need to relax a little.

Tusch said:

Not really true, it is no longer a common recommendation to do boils for mead and this is straight from Hightest's mead FAQs and pdf's http://home.comcast.net/~mzapx1/FAQ/Refractometer.pdf
I believe he uses refractometers exclusively allowing him to take many more readings to more accurately track a fermentation without having to worry about taking too much out for hydrometer samples

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OK, I shall revise my statement to 'pre-fermentation', forgot about the mead guys that don't boil...

I know you can use the refractometer during/after fermentation, but you have to get rid of the alcohol produced first and it's just more of a PITA than I'm willing to put up with.

You don't have to "get rid" of the alcohol, you just have to account for it, with correction factors that are easy to figure if you took an initial, pre-pitch, refractometer reading.

Perhaps difficult for anyone not comfortable with a little algebra, but generally not too much hassle for those amongst us who have science, engineering, or computer science backgrounds.

<--- Majored in microbiology, worked in a lab for a few years, currently works as a web developer... Just saying.

The OP asked a question, I answered with my opinion. I am still allowed to have an opinion, aren't I? Sheesh people.

wayneb said:

Perhaps difficult for anyone not comfortable with a little algebra, but generally not too much hassle for those amongst us who have science, engineering, or computer science backgrounds.

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Gremlyn1 said:

...I know you can use the refractometer during/after fermentation, but you have to get rid of the alcohol produced first...

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Actually, you do not need to "get rid of the alcohol..." to obtain a useful refractomer reading during fermentation.

I will admit that you must do more than simply read the refractometer, but the small amount of extra effort is worth it (IMO). In addition, you must have taken a OG as it is used in the calculation that corrects for the presence of the EtOH.

There are a few online sites that offer this correction calculation as well as my Mead Calculator spreadsheet. Even though I have several hydrometers, it is a rare occurance when I use one...

I don't remember where I read it, but when I first got my refractometer, I read a prcedure that involved evaporating off the ethanol from the beer. I didn't look much further into it after reading that. Of course, now I can't find that procedure...

or just use an online calculator
http://onebeer.net/refractometer.shtml
http://slobrewer.com/mobile/refract.html

Gremlyn1 said:

<--- Majored in microbiology, worked in a lab for a few years, currently works as a web developer... Just saying.

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Funny, I didn't think I was doing more than correcting an erroneous statement, for the record. Your opinion is certainly of value, but as a microbiology major who worked in a lab environment you should appreciate the need for accuracy and comprehensive explanations when providing information to folks who may have little to none of the experience base that you have... Just saying.

Well said...

FWIW, I read your post as a bit of a slap-down, too. It's the Internet, it happens, no harm.

On topic, I like the old school, simple technology of the hydrometer. Easy, accurate, no electronics involved.

wayneb said:

Funny, I didn't think I was doing more than correcting an erroneous statement, for the record. Your opinion is certainly of value, but as a microbiology major who worked in a lab environment you should appreciate the need for accuracy and comprehensive explanations when providing information to folks who may have little to none of the experience base that you have... Just saying.

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wayneb said:

Funny, I didn't think I was doing more than correcting an erroneous statement, for the record. Your opinion is certainly of value, but as a microbiology major who worked in a lab environment you should appreciate the need for accuracy and comprehensive explanations when providing information to folks who may have little to none of the experience base that you have... Just saying.

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Fair enough, I think your post just came across the wrong way is all. I wish I could find the procedure I read that gave the idea in the first place. I was searching feverishly last night for it... I think it came with my refractometer.

Yeah, I'd like to know where it came from, too. It seems an odd process to recommend, since any alcohol evaporation also would cause some water to evaporate, so you'd be concentrating the must in the process. And apologies if my first post seemed a little snitty. I didn't think it was at the time, but sometimes I type faster than I think!

Pappers said:

On topic, I like the old school, simple technology of the hydrometer. Easy, accurate, no electronics involved.

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But electronics make EVERYTHING better! (Grin) If you really want to avoid electronics, the $30 refractometers just use optics and you can do the conversion to SG with pencil and paper or a slide rule.

On second thought, that does sound like a lot more work.

Dave

Gremlyn1 said:

I don't remember where I read it, but when I first got my refractometer, I read a prcedure that involved evaporating off the ethanol from the beer. I didn't look much further into it after reading that. Of course, now I can't find that procedure...

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You're not crazy. There is a method you can use to boil off the alcohol. I read about it too but since I've never needed to do such a thing I didn't commit it to memory.

I think I was reading about it on another forum in the context of removing the alcohol so you could determine residual sweetness, for back-sweetening a wine. I think there was no known OG either, which made it hard to determine how 'dry' the FG really was since the higher ABV of a wine gives you a 0.999 or lower FG and doens't help you know how much sugar is actually left.

wayneb said:

Yeah, I'd like to know where it came from, too. It seems an odd process to recommend, since any alcohol evaporation also would cause some water to evaporate, so you'd be concentrating the must in the process.

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Ethanol boils at something like 173F, so if you heat your sample carefully you'll cook off the alcohol without losing (much) water. (That's what distillers do so they don't dilute their hooch.) I can see doing that if you want to use the refractometer to measure residual sugar in your fermented must.

But from what I read here and elswhere most homebrewers / vintners are more interested in alcohol content at this stage, not sugar contant.

If I'm wrong, somebody please correct me. I'm here to learn.

Dave

No Dave, you are correct in your assumption. The "still tailing" technique would make sense if you're after a residual sugar measurement, but it does seem like a lot of extra work (and I still have concerns about introducing errors from some water evaporating) for an estimate of ABV, which is how we usually gauge the state of a fermentation.

Hinermad said:

But electronics make EVERYTHING better! (Grin) If you really want to avoid electronics, the $30 refractometers just use optics and you can do the conversion to SG with pencil and paper or a slide rule.

On second thought, that does sound like a lot more work.

Dave

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Maybe I could use an abbaccus?

Pappers said:

Maybe I could use an abbaccus?

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Never used one myself, but I worked with a lady whose father grew up in Hong Kong. She said he used one to do his taxes and it worked for everything except division. If he had to divide something he'd grab a paper and pencil and do it longhand. (And this guy was a university chemistry professor, so he knew his way around arithmetic.)

Dave

wayneb said:

it does seem like a lot of extra work (and I still have concerns about introducing errors from some water evaporating) for an estimate of ABV, which is how we usually gauge the state of a fermentation.

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So it is possible to estimate the SG of fermented must with a refractometer, and from that estimate the alcohol content (given the OG), without removing the alcohol from the sample? Or have I misunderstood something?

The reason I ask is that I started a couple of batches of mead and took OG readings with a hydrometer before I bought a refractometer. Since then I've used the refractometer to estimate their SG using MoreBeer's wine spreadsheet (here if anyone's interested), but I don't really have any way of verifying the spreadsheet's results short of pulling larger samples and using the hydrometer. Since they're only 1 gallon batches I'm reluctant to throw that much away. I do plan to make one more hydrometer reading on each of them before I bottle to get the final answer, and I guess I'll know then how far off the refractometer was.

Dave

Hinermad said:

So it is possible to estimate the SG of fermented must with a refractometer, and from that estimate the alcohol content (given the OG), without removing the alcohol from the sample? Or have I misunderstood something?

Dave

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You have not misunderstood. You can indeed do this, and Hightest has included a correction as part of his Mead Calculator spreadsheet to do exactly that. If you've never looked at his calculator before, it is worth checking out (see the sticky at the top of this Mead forum for Hightest FAQs). Once you set up the spreadsheet for initial amounts of ingredients, you can then enter a Brix measured at any time during the ferment and get a corrected SG. That can be used to accurately estimate ABV at any point in the fermentation.

BTW, MoreWine's calculator is simpler to derive corrected Brix values, but it doesn't do all the other handy things that Hightest's can do for you!

wayneb said:

BTW, MoreWine's calculator is simpler to derive corrected Brix values, but it doesn't do all the other handy things that Hightest's can do for you!

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I'll give Hightest's spreadsheet a look then. I modified the MoreWine sheet to compute ABV from the estimated SG but it was just a hack to see if I could do it.

Thanks for the help!

Dave

Hinermad said:

I'll give Hightest's spreadsheet a look then. I modified the MoreWine sheet to compute ABV from the estimated SG ...

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An ABV calculation is present in my spreadsheet, which is more sophisticated as it is also influenced by the FG (a somewhat more advanced topic I've discussed before, re: ABV vs. ABW FAQ).