hydrometer vs refractometer and other issues

[Timofey Gorlov]

Yesterday I finished my primary fermentation of my blackberry cider. This is my first experience. I measured final gravity with refractometer and hydrometer (see the pictures). Refractometer shows measurement for clear water and for my fermented cider/wine. You see the hydrometer shows dry cider but hydrometer measures 5 Brixx (1.020 gravity). Is my refractometer wrong or all refractometers are wrong?
Another question. For second fermentation/carbonation I added raw raspberry juice without any extra sugar.
How long will it take to perform full fermentation/carbonation in a sealed bottle?
I know that for sugar it would take about 1 week but what about fruit juice?

 

[beermanpete]

The refractometer is designed to measure sugar content and does not work well in the presence of alcohol. The hydrometer is correct.

 

[kh54s10]

You have to run a correction when using a refractometer with the presence of alcohol. Brewers Friend site has one.

 

[Oginme]

Your refractometer is calibrated for solutions of sugar in water. Once alcohol is present, it is no longer valid for direct measurements. The figure needs to be corrected for the presence of the alcohol and the percent of alcohol. There are converters on-line which in combination with the starting Brix or gravity will give you the actual gravity of your fermented cider.

 

[Timofey Gorlov]

The refractometer is designed to measure sugar content and does not work well in the presence of alcohol. The hydrometer is correct.

I think they both supposed to measure sugar content by two different ways.

 

[Timofey Gorlov]

Your refractometer is calibrated for solutions of sugar in water. Once alcohol is present, it is no longer valid for direct measurements. The figure needs to be corrected for the presence of the alcohol and the percent of alcohol. There are converters on-line which in combination with the starting Brix or gravity will give you the actual gravity of your fermented cider.

So it should work correctly only for starting measurement before all fermentation?

 

[BrewInspector]

Yes.

You can use the refractometer to determine progress and completion but the readings will be inaccurate once alcohol is present and must be converted.

Using to the refractometer will use less of the product for each test over using the hydrometer. The hydrometer will provide a correct reading in all stages.

 

[Robert65]

Above posts referencing correction are right. Refractometers are calibrated to sugar solutions, and alcohol, have a different refractive index, throws the reading off. I can attest that with correction, a refractometer is as accurate as a professional grade, narrow range hydrometer. The calculator at Brewer's Friend is very good.

 

[Timofey Gorlov]

O, thanks for educating me. Now refractometer + caclulator works well and agrees with hydrometer measurements.
What about the second question, how much should I wait for the secondary fermentation with pure juice? I definitely don't want to open the bottles until it's ready.

 

[kh54s10]

Are you asking about secondary during the fermentation process or bottle conditioning for carbonation.

If secondary without carbonation there will be no further fermentation unless you are adding more juice/sugars. That step is mostly for allowing the cider to clear (for more sediment to drop out of solution). If for carbonation that should take about 3 weeks at room temperature. It will vary some.

 

[Timofey Gorlov]

Are you asking about secondary during the fermentation process or bottle conditioning for carbonation.

If secondary without carbonation there will be no further fermentation unless you are adding more juice/sugars. That step is mostly for allowing the cider to clear (for more sediment to drop out of solution). If for carbonation that should take about 3 weeks at room temperature. It will vary some.

I had fully dry cider after primary fermentation as you can see. After that I added raspberry juice that contains natural fructose sugar so it should start fermenting and carbonating again in the sealed bottles.

 

[kh54s10]

I had fully dry cider after primary fermentation as you can see. After that I added raspberry juice that contains natural fructose sugar so it should start fermenting and carbonating again in the sealed bottles.

I'm not really familiar with carbonating ciders. But, if you use too much sugar (fruit juice) you could get very over carbonated cider. I believe those growlers would release excess pressure from the caps, but be careful that you don't produce enough pressure to explode the bottles.

 

[Redpappy]

I have been debating on getting a refractometer, just to simply some things for me. I have noticed that there is an alcohol refractometer. Has anyone tried these?

 

[Robert65]

https://hannainst.com/hi96841-digital-refractometer-for-beer.html

 

[kh54s10]

https://hannainst.com/hi96841-digital-refractometer-for-beer.html

$180 and you still have to correct for the presence of alcohol...

 

[Robert65]

$180 and you still have to correct for the presence of alcohol...

Yes, but at least you get the correct reading. I quit messing around with the handheld optical units and don't regret it, especially as they can cost a big chunk of that price and can be very difficult to read and interpret unambiguously. Just something to consider.

 

[kh54s10]

Yes, but at least you get the correct reading. I quit messing around with the handheld optical units and don't regret it, especially as they can cost a big chunk of that price and can be very difficult to read and interpret unambiguously. Just something to consider.

$30 is a big chunk of $180??? I don't find the optical ones difficult to read or interpret. I just read the gravity scale. I checked mine against the Brix and it is accurate. And I saved $150....

Edit changed the period after $180 to question marks.....

 

[Soulshine2]

Yesterday I finished my primary fermentation of my blackberry cider. This is my first experience. I measured final gravity with refractometer and hydrometer (see the pictures). Refractometer shows measurement for clear water and for my fermented cider/wine. You see the hydrometer shows dry cider but hydrometer measures 5 Brixx (1.020 gravity). Is my refractometer wrong or all refractometers are wrong?
Another question. For second fermentation/carbonation I added raw raspberry juice without any extra sugar.
How long will it take to perform full fermentation/carbonation in a sealed bottle?
I know that for sugar it would take about 1 week but what about fruit juice?
View attachment 637856 View attachment 637857 View attachment 637858

do you know the temperature at which your hydrometer calibrates ?
Have you done that to make sure it reads correctly? Mine is 60*F ,others are 66*F . Also , mine is a triple scale where it appears yours is not.

 

[Timofey Gorlov]

I'm not really familiar with carbonating ciders. But, if you use too much sugar (fruit juice) you could get very over carbonated cider. I believe those growlers would release excess pressure from the caps, but be careful that you don't produce enough pressure to explode the bottles.

Thanks.

I have been debating on getting a refractometer, just to simply some things for me. I have noticed that there is an alcohol refractometer. Has anyone tried these?

I think "alcohol refractometer" still means gravity and alcohol refractometer. There is no magic in physics that would allow to measure optical refraction of alcohol content only.

do you know the temperature at which your hydrometer calibrates ?
Have you done that to make sure it reads correctly? Mine is 60*F ,others are 66*F . Also , mine is a triple scale where it appears yours is not.

Calibrated at the 75F and took measurement at the same temperature.

 

[Timofey Gorlov]

I have been debating on getting a refractometer, just to simply some things for me. I have noticed that there is an alcohol refractometer. Has anyone tried these?

Actually, another alcohol refractometer 0-80% that measures directly alcohol of dry drinks can do this. I'm wondered why my refractometer doesn't have the third scale to measure the alcohol directly.

 

[Soulshine2]

Thanks.

I think "alcohol refractometer" still means gravity and alcohol refractometer. There is no magic in physics that would allow to measure optical refraction of alcohol content only.

Calibrated at the 75F and took measurement at the same temperature.

Um. Yours calibrates at 75?? Or you took the reading at 75? If the latter, did you make the adjustment for the temperature difference?

 

[kh54s10]

Actually, another alcohol refractometer 0-80% that measures directly alcohol of dry drinks can do this. I'm wondered why my refractometer doesn't have the third scale to measure the alcohol directly.

I don't believe this is true. I have never heard of one.

And I found this: https://blog.eckraus.com/wine-refractometer-alcohol-tester

 

[Timofey Gorlov]

I don't believe this is true. I have never heard of one.

And I found this: https://blog.eckraus.com/wine-refractometer-alcohol-tester

Oh, no you are not right, if you have sugar in your alcohol then you cannot do ethanol measurement but if you have ethanol only then you can measure it. Try to search "0-80% alcohol refractometer" in amazon and you will see.
You only need to make sure that wine or beer is dry.

 

[kh54s10]

Oh, no you are not right, if you have sugar in your alcohol then you cannot do ethanol measurement but if you have ethanol only then you can measure it. Try to search "0-80% alcohol refractometer" in amazon and you will see.
You only need to make sure that wine or beer is dry.

I read that and it might give you some Alcohol percentage of a highly distilled alcoholic beverage. I am almost certain that it won't give you useful information in a sugary cider, sweet wine and definitely not in a beer.

IMO, Most beers, wines and ciders are not going to be dry enough for that refractometer.

And I would say the people at E.C. Kraus probably know what they are talking about.

 

[Katman]

I do not regret buying a refractometer ($20@amazon) one bit. I use both and compare them for OG and FG they always match up, using a correction calculator for FG. When checking for stable gravity before bottling it sure is nice to only have to use a couple of drops to see if the beer is done fermenting.