My Brand New Refractometer

[Mexibilly]

Just got a refractometer, courtesy of my employer, my tool allowance, and a fastenal catalog that ended up on my desk.
Whatever I use to take the sample must be sanitized.
Given that it only takes a few drops, will the fact that there's a tiny bit of StarSan in the sample throw off the reading?
What are the popular methods for taking an accurate refractometer sample?

 

[h22lude]

Why do you need to sanitize it? If you are checking gravity at the end of your boil, just take a small sample and cool it. No need to sanitize anything. If you are taking it before pitching, just sanitize the item you use to take the sample. You can use a small pipette. I just stick a small cup in. Not the best way but I ran out of pipettes lol You don't need to sanitize the refractometer at any point because you aren't putting that small sample back in.

 

[maffew222]

Yes, small amounts of star san will throw off the reading, speaking from experience. I use a sanitized glass pipette and pick up a few ml of wort, then drop it out, then pick up a few more which I measure with.

But like the other poster said, for preboil Gravity you don't need to sanitize anything, and I usually just get my starting gravity from the wort left in my boil kettle after transferring to my carboy. Then later I grab terminal gravity from the last bits coming out of the fermenter when I rack to a bottling bucket. No sanitizing needed really.

 

[Hoppity]

Whatever I'm stirring with drops the sample across the lens. No temperature correction needed afaik. I usually take several samples to make sure it is blended.

 

[h22lude]

No temperature correction needed afaik.

Some units have auto temp compensation (ATC) and some don't. Though I do remember reading a few times that even the ones with ATC, the samples should be cooled a little. With such a small sample, I just stick it in my freezer for a minute.

 

[Hoppity]

Some units have auto temp compensation (ATC) and some don't. Though I do remember reading a few times that even the ones with ATC, the samples should be cooled a little. With such a small sample, I just stick it in my freezer for a minute.

Good to know, now I'll have to check mine. As a practice, I typically read within a minute of sample drop.

 

[pablosbrewing]

ATC for a refractometer refers to the (room) temperature of the instrument, not the temperature of the few drops of the sample. So when it's cold outside keep the refractometer inside the house.

 

[Hoppity]

ATC for a refractometer refers to the (room) temperature of the instrument, not the temperature of the few drops of the sample. So when it's cold outside keep the refractometer inside the house.

So...sounds like we need a primer or sticky on proper refractometer use. My directions are long gone. Can we establish a "Best Practices" document?

 

[dk21]

I just sanitize a stainless 1/8 teaspoon, then stick it under the flow of wort from my kettle to the fermenter. This rinses any excess Star San off.

 

[doug293cz]

Also, you need to know (if you don't already) that refractometer readings are affected by the presence of alcohol. Once fermentation has started, you need to use a calculator to correct for the presence of alcohol in order to get a reasonably accurate value of SG. Probably the best refractometer calculator is here: http://seanterrill.com/2012/01/06/refractometer-calculator/.

Brew on

 

[Mexibilly]

This is an ATC refractometer. I don't take a preboil gravity, I generally take one just before pitching, maybe at transfer to secondary and when I bottle.
To sanitize an eye dropper, take a few small shots and put down the drain then put a sample on the glass sounds like the best plan. I hadn't considered that I didn't necessarily need to use the first sample I drew.
Thanks guys.

Primary: Heady Nugs
Secondary: W00t Stout
Bottle: Hop Head & Pumpkin Twist

 

[Clonefan94]

I usually take a pre boil reading. No worry about sanitizing there. Then after the boil, I already have a stainless spoon that I've had in sanitizer for stirring during cooling. At some point during cooling, I just pour off a small scoop from the spoon into a small plastic cup and use that as my sample for the refractometer. This way the large spoon has already been sanitized and I'm no worrying about adding another item that needs sanitation. Plus I allows me a little time in case I can't get to the sample right away.


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