Refractormeter usage

[TimK]

I recently purchased a Refractometer from Morewine (the RSG-100/act. #MT700) to help in my early wine making adventure. Here's my issue. I calibrated to 0 and when I did, I definitely saw the hard line between the blue and white areas when I looked through the eye piece. But as I use it to check the Brix during fermentation (Malbec) there is nothing close to a hard line to really tell where the reading is at. The blue and the purple shade together that I feel like I am guessing at this point. And the guessing is within a 5 Brix difference which of course is huge. I have tried a bunch of minor things (less juice, more juice, filter the juice as much as possible, don't filter at all, different lighting, etc..). I started to wonder maybe I am color blind and those colors are not as definite for me. (Which can still be true, but I had my son look into it and he saw the same blurry mixture). I guess I am wondering if this is normal or not. Or any ideas to try to get a clearer reading. I know I did not go out and buy the top of the line refrac, but it should still be helpful not stressful.
Thanks for the help.

TimK

 

[cintipam]

Hi Timk

there is an entire thread about refractometers in the forum about tools tutorials etc. It basically states that once fermentation has started, you can't get an accurate reading from one. So it is not your eyes. Worth a read. I would say the only possible route is to use a hydrometer pre ferm and keep records so you can calculate the change pre and post ferm to know your alch percentage etc. Keeping track this way also helps you know if you have a stuck ferm much sooner than just noticing ferm is taking way too long.

http://www.winemakingtalk.com/forum/showthread.php?t=51464

Pam in cinti

 

[bchilders]

Hi Tim, you should certainly read the tread mentioned by Pam. Refractormeters are calibrated to read sugar levels in water and work best with raw fruits or juice. I use mine to test grapes in the field to determine when to harvest. Once fermentation starts and alcohol is present the readings will be off. I suggest using a Hydrometer and take a reading before you pinch the yeast and then again in 5 to 7 days and then every day or so till you get a reading of .995 or less if you going for a dry wine. Winemaker Mag has a good article on this.

 

[Boatboy24]

Good advice in the first two replies. What I do is check the brix prior to fermentation. I then convert that to SG. From then on, I just measure SG with my hydrometer. Here's a good brix to SG conversion calculator: http://www.brewersfriend.com/brix-converter/

 

[TimK]

Thanks for the replies. I probably didn't read enough into it then, because I went the Refractometer route. Mainly because doing a small batch for my first time I didn't want to waste to much of the wine when checking with hydrometer. Early mistake I guess. I will take a look at the links and go from there. My wonder now is if I didn't start with a hydrometer, I am guessing I won't know the ABV in the end. Am I right to think that?

 

[GreginND]

You don't have to waste the wine with a hydrometer. Just pour it back in when you are done measuring.

 

[TimK]

I thought that it is not wise to put the sample for the hydrometer back in the batch.

 

[bchilders]

I thought that it is not wise to put the sample for the hydrometer back in the batch.

If you sanitize all the parts the wine touches than there is no reason not to add it back. I keep a spray bottle of sanitize solution of SO2 and spray anything that might contact the wine and then rinse with distilled water just before use. Just don't get confused with samples for TA or FSO2 testing, those have to be trashed.

 

[salcoco]

http://valleyvintner.com/Refrac_Hydro/Refract_Hydro.htm

this link will discuss how a refractometer can be used during fermentation and provides a spreadsheet that has incorporated the math to correct the brix reading during fermentation. I have checked this spreadsheet measurements and corrections with a hydrometer a number of times and have found it to be correct. it is certainly easier to use one drop of wine to measure then using a holding jar.
I use a digital refractometer so I do not have the blurred line problem you speak to.

 

[TimK]

Good to know that it is fine to put sample back. (On certain samples of course). That definitely helps with not losing so much of the goods. As for the Refractometer, I only have an analogue (if you will) one. Readings not as clear. Looking at the digital version, that would be the way to go. Next investment. Thanks for all the help. I really dig these forums!
TimK

 

[TimK]

Getting back to the hydrometer, I took a sample out of the must and used a mesh bag (doubled up) to filter out the solids. But the sample still had some particles in it that seems "thicker" then I think it should be. How much will it affect the hydrometer reading? I tried to pour a little in a coffee filter, but it was taking forever for the wine to filter through. How much does the wine have to be filtered before it gives an accurate reading with a hydrometer? Thanks.
TimK

 

[sour_grapes]

Tim, don't worry about suspended solids. The effect is negligible. The density of the particles in suspension is pretty close to the density of the liquid (or else those particles would fall out of suspension quickly). The density really responds a lot more to dissolved solids.

 

[TimK]

Makes sense. Good to know that the reading of 1.010 was not compromised. Fermentation has been slow (day 11) and I was starting to get nervous that I would not be able to confidently know the end point. Thanks.

 

[richmke]

Your original question was about the blurry line. I am color blind, and I also bought a cheap refractometer off ebay. As I recall, the line was clear enough.

IMHO, the refractometer is helpful at getting the Starting SG, and as a quick check along the way (especially if I am doing a small batch, and it is a pain to float a Hydrometer). Whether fermentation is done (I give it more than enough time), and where it ended is not so important to me.

The hydrometer is the way to go if you want precise numbers.

 

[TimK]

Thanks for the input everyone. After reading the posts and doing other reading, the hydrometer seems to be the way to go in the beginning and use the readings as the guide in the end. I will still use the refractometer along the way as an additional measurement.
richmke, I might have to invest in an even cheaper refractometer to see if there is any difference. The initial reading before ferm is clear enough. After fermentation has set in though, I can get a rough idea where the line is but not as clear as I would want. I do agree the hydro is the way to precise numbers.
Thanks again
Peace
TimK