Gravity sample from sanke fermenter

[bwarbiany]

I typically don't mess with FG readings during fermentation, as I generally use a pretty consistent process with known yeasts, and kegging makes it unnecessary to worry about bottle bombs.

But I've got a saison in the fermenter right now, and I want to make sure it's fully fermented and not stalled before I get it out. I haven't used this yeast before, so I'm a bit more paranoid about the process than usual.

I'm using the sanke keg fermenter w/ Derrin's kit, but I'm not sure the best way to get some liquid out of there... Anyone have any good methods?

[JonW]

I use this wine thief: http://www.midwestsupplies.com/fermtech-wine-thief.html

It works perfect.

[bwarbiany]

I think I'm thinking more along the lines of this:

http://www.amazon.com/Samco-Scientific- ... B003Z6Q6AO

I'd plan on using a refractometer and then adjusting the value using Beersmith to get FG.

Is 12" long enough to get at my beer (it's about 10-11 gal in the sanke)?

Anyone know where I can buy these in packs smaller than 100? Or is anyone interested in doing a group buy on these?

[JonW]

Test out how far you need to reach in with a dip stick. I think 12" should be fine since the pipette will suction the volume up versus the wine thief where you need to submerge further.

I only use my refrac for OG. I always use the hydrometer for FG and then I get to drink the sample as a bonus!

[rex]

+1 for the wine thief.

Refractometer is pretty bad for taking FG - there are formulas to correct the reading but it will never be as accurate as a hydrometer. The only time I use my refractometer is for checking SG during the various stages of mashing/sparging.

[bwarbiany]

+1 for the wine thief.

Refractometer is pretty bad for taking FG - there are formulas to correct the reading but it will never be as accurate as a hydrometer. The only time I use my refractometer is for checking SG during the various stages of mashing/sparging.

I've heard different. One of the guys over on beeradvocate typically uses his refractometer for FG, and with the formula to correct, it's always within .001 SG of the value his hydrometer tells him. Obviously you need to know the OG for the formula to work, but OG is the one thing that I *always* measure.

[bwarbiany]

I ended up just going with the thief route (since I already have one), so I sterilized it, sanitized it, and got my sample for both the hydrometer (and since I was pulling the sample, grabbed the refractometer too). That's where it got interesting.

The refractometer measured 7.1 brix. Given an OG of 1.067, that corrects out to an SG of 1.004.

I then checked with the hydrometer. It read 1.008, and that was at a temp of 82 degrees, which corrects to 1.011.

A difference of 7 SG points between two instruments is a bit worrying.

So I checked the hydrometer in tap water. Also at ~82 degrees, it registered 1.003. Using a temp correction, that gives me 1.006, so it appears that my hydrometer is off by 6 SG points.

Looks like the refractometer was accurate after all

[JonW]

You need to do your test with distilled water, not tap water.