Refractometer question

[mikefrommichigan]

I thought I was having a problem with a couple of kits I started 2 weeks ago. I took an initial SG reading with a hydrometer reading of 1.090, just what I was hoping for. I borrowed a refractometer from a friend to take subsequent reading, as it is a lot easier to check the SG with a refractometer. This is the first time I have use one. I checked the brix values daily and converted them to SG values. After a week the values seemed stuck on 7 degrees Brix, approx 1.028 SG. This went on for nearly a week, without a change in values.

This morning I rechecked the refractometer calibration with distilled water and it was correct. I decided to check the SG with the hydrometer and the reading was 1.0. I rechecked with a second hydrometer I have and it also read 1.0.
I drove over to my friends house as he was brewing some beer, and we checked his beer with both the refractometer and a hydrometer. They both read the same. 1.045 SG, approx 11.0 degrees brix.

So why the discrepancy with the wine readings?

If anyone has an explanation I would like to hear it.

Thanks

 

[dralarms]

You can't use a refractometer to read sg or brix in wine, only must. Once it becomes wine your reading will be off.

 

[mikefrommichigan]

Thanks. Since reading your post I did a little bit of research and found various links stating the same thing.

From the university of Minnesota and other sources

The Brix scale should only be used when measuring the sugar quantity in grape juice. You should not be using it to track the fermentation of your wine.

Once fermentation begins, a hydrometer should be used to measure the specific gravity of your wine

 

[tmmii]

Refractometer measures light bending, the alcohol affects how the light bends and changes the reading.


Sent from my iPhone using Wine Making

 

[Norske]

I use the refractometer all the way thru by using a spreadsheet developed by Morewine. It is developed to take into account the alcohol. I always double check the beginning and ending with my hyrdometer and so far, this spreadsheet has been spot on each time. Here is a link.

http://morewinemaking.com/content/winemanuals

 

[mikefrommichigan]

Great Spreadsheet, thanks for the link. I may keep on using the refractometer now, as it is a lot easier to take a sample than using a hydrometer, and do as you suggest and double check at the beginning and the end with a hydrometer.

 

[salcoco]

follow the spreadsheet. 7 brix usually means the fermentation is complete.

 

[RegionRat]

I use the refractometer all the way thru by using a spreadsheet developed by Morewine. It is developed to take into account the alcohol. I always double check the beginning and ending with my hyrdometer and so far, this spreadsheet has been spot on each time. Here is a link.

http://morewinemaking.com/content/winemanuals

I too have a refratometer. When I got it I thought I was BMOC. Then I got confused on the readings I was getting as the must fermented. After asking questions and reading I came to this conclusion.

The digital one I have is great for measuring fruit on the vine for sugar content. The reason being only a few drops of juice are needed to test sugar. Aiding me in determining when the sugar content is high enough to warrant me picking fruit.

I found using the spread sheet from Morewine is accurate but just a pain in the ***. It is easier to just draw a sample of must and drop in a hydrometer. The stuff I do I dont need to know the exact sg till the ferment reaches around 1.010, then I rack the must under and airlock, or snap the lid down tight on the fermenter. Then I need to know it hasnt changed in a few days.

The next time I need a hydrometer is many months later. Then I use a narrow range hydrometer or finishing hydrometer (.980-1.02)to back sweeten. This time I do care about accuracy. I do bench trials by adding sugar to samples till I get to the sweetness I like. I take a reading with a narrow range hydrometer and do the math to figure out the sugar needed to sweeten the whole batch.

RR