Refractometer

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I'm not sure what's going on with my refractometer. I take a reading in my hydrometer with demineralised water, 1.000.

Draw off a sample and the reading in my refractometer is also 1.000. So far so good.

Take a sample from my batch that has been going for 10 days. Hydrometer reading, 1.010. Draw a sample off that for the refractometer and it reads 1.020.
 
Black Devil Dog said:
Take a sample from my batch that has been going for 10 days. Hydrometer reading, 1.010. Draw a sample off that for the refractometer and it reads 1.020.
Could be the temperature of the sample?
 
Black Devil Dog said:
I'm not sure what's going on with my refractometer. I take a reading in my hydrometer with demineralised water, 1.000.

Draw off a sample and the reading in my refractometer is also 1.000. So far so good.

Take a sample from my batch that has been going for 10 days. Hydrometer reading, 1.010. Draw a sample off that for the refractometer and it reads 1.020.
To use a refractometer after the ferment has begun you need to apply an alcohol correction. Search for "refractomoter alcohol correction" and you will find charts and calculators. Also most brewing software has a calc built in. You need to know the starting gravity.
 
Black Devil Dog said:
I'm not sure what's going on with my refractometer. I take a reading in my hydrometer with demineralised water, 1.000.

Draw off a sample and the reading in my refractometer is also 1.000. So far so good.

Take a sample from my batch that has been going for 10 days. Hydrometer reading, 1.010. Draw a sample off that for the refractometer and it reads 1.020.
Fermenting or fermented wort gives an incorrect reading due to the presence of alcohol.
There are complicated calculations that account for this to give a true result.
Beersmith has a tool for determining the correct reading

EDIT: what Kev said
 
QldKev said:
To use a refractometer after the ferment has begun you need to apply an alcohol correction. Search for "refractomoter alcohol correction" and you will find charts and calculators. Also most brewing software has a calc built in. You need to know the starting gravity.
Argh why didnt i think of that... Oh I answered a question before caffeine kicked in. :blush:

http://onebeer.net/refractometer.shtml is the calculator I use.
 
Refractometer_Calculations.jpg

This one works for me.
Gets me to no more than one point different to a check with my hydrometer, at worst. At best it's the same. I now just use the refractometer.


Edit: I no longer know the source of this, so can't acknowledge it, unfortunately.
 
Just done my first brew day with refractometer at hand. How freaking easy! Mine left no guess work
Haven't used it during fermentation though.
 
Put down a RIS yesterday and was having some crazy discrepancies with my refract and hyrdo samples. I've calibrated the 2 with distilled water and they've been agreeable on all previous brews. In the end my hydro sample read 1.090 and the refract was 1.080. Does the black as night wort make a difference to the refract?
 
Endo said:
Argh why didnt i think of that... Oh I answered a question before caffeine kicked in. :blush:

http://onebeer.net/refractometer.shtml is the calculator I use.
I just used this calculator......

OG = 1.095 = 22.5 Brix

The brew has been in the primary for 8days. Today i took a sample & it was 10 Brix on the refrac. I punched the info into the onebeer calc & it said the new SG is 1.006. A hydrometer reading is 1.026. Where is the difference coming from?
 
alcohol is the simple answer there are converters to allow for this
 
Yeah but is'nt the calculator supposed to take care of that??
 
Foster said:
Yeah but is'nt the calculator supposed to take care of that??
Yes, that calculator should take care of the alcohol issue. Although I haven't delved into it too deeply so I'm not sure how accurate this calculator is. With your info, this calculator gives FG = 1.009, but this one gives 1.006 again. So I'm not sure which one to believe.

EDIT: Also. if alcohol was the answer, wouldn't the brix reading be too high, not too low?
 
Maybe there are CO2 bubbles clinging to your hydrometer and causing the reading to be too high. Although, in my experience that only changes it by a couple of points, not 20.

Are you sure your hydrometer is calibrated correctly? Also, what temp was the sample when you measured it. That makes a bigger difference than the CO2 thing.
 
Im positive the sample had no bubbles in it. The sample temp was 20deg, & yeah the hydrometer is calibrated. I will take another sample later.....
 
Foster said:
Im positive the sample had no bubbles in it. The sample temp was 20deg, & yeah the hydrometer is calibrated. I will take another sample later.....
10 brix = 1.040.
Referring to the chart warra48 posted, if you estimate a line further left for an OG of 1.095, 1.040 would cross somewhere around 1.010.

Refer here for a chart suitable for your brew.
http://aussiehomebrewer.com/gallery/image/7989-refractometer-sg-alcohol-correction-chart-for-og-range-1070-to-1120/

Result of around 1.006. That's extreme attentuation, I'd be double-checking your refractometer reading. Hydrometers rarely lie unless the temp of your liquid is well outside 20°C.
 
TheWiggman said:
10 brix = 1.040.
Referring to the chart warra48 posted, if you estimate a line further left for an OG of 1.095, 1.040 would cross somewhere around 1.010.

Refer here for a chart suitable for your brew.
http://aussiehomebrewer.com/gallery/image/7989-refractometer-sg-alcohol-correction-chart-for-og-range-1070-to-1120/

Result of around 1.006. That's extreme attentuation, I'd be double-checking your refractometer reading. Hydrometers rarely lie unless the temp of your liquid is well outside 20°C.
Thx Wiggman.

I just took another reading - 24 hrs after the previous.

Refrac = 12 Brix

Hydrometer = 1.022

The calculator shows 1.019.

like you i believe the hydrometer. The calculator is alot closer today..Not sure why, all conditions are the same...
 
How do yáll take a sample from the fermenter before you throw the yeast in to get your OG?

I've been teaching a mate home brewing and doing partials/extracts, I jumped straight from K&K to All-Grain so I missed this step. With all grain you just sample from the kettle with a refract or hydrometer and u can always get a clean mixed sample.

The last 2 brews I've done with my mate I couldn't get a proper reading, so they have hit the fermenting fridge without a recorded OG

e.g., brewed an extract IPA this arvo with him, if u use the pipet to draw off a coupla drops from the top of the fermenter (im using cubes to ferment, so its a small hole and u have to hold them on an angle to reach the wort with the pipet (I have shaken to mix)), I get a really low reading, both recently have been around 1.020, when clearly the IPA was dark and malty and should have been around 1.065, and Tuesdays brew should have at least been around the 1.038 mark. I then also drew off from the tap at the bottom of the cube, with visually a bit of hops material in, I got a reading of 1.084..

Fuked if I know, I coulda stuffed around shaking the cube and letting it settle a while then drawing of a sample, and I know its bad practise not recording an OG, but it was annoying after about 6-7 goes, so off it went into the ferm fridge.

The Refrac was then checked with clean 20*c water after both fuk arounds and read correctly.

Pretty hard to teach a mate good practise when this annoying crap happens.

Im putting it down to the wort not mixed all up properly and left a while for the solids to settle before drawing off a sample, but surely there is an easier way for the guys doing extract/partials.
 
Maybe a wine theif would fix this problem so im drawing off wort from the centre of the cube, but then I don't wanna buy one just for training purposes.

Mmmmmmmmmmmmm
 
Errrrr..... Are you boiling that wort?

If not, use the standard kit advice of dissolving the malt extract into warm or hot water before you add to the cold water to get to pitching temp. I mean, coopers say to sit their can in hot water to make it easier to dissolve - just common sense.
 

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