Help with Brix hydrometer

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DonutBrew

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Hey guys,
I brewed a lager with a friend in another city about 3 1/2 weeks ago, I brought all my equipment, he supplied the stove, carboys, and basement for cool fermenting temps. We measured the OG with my hydrometer (1.040) and expected to get to under 1.010. Now, the problem is all he's got to measure the FG with is some wine-making hydrometer that only has a Brix scale. It's not a refractometer, but a smaller hydrometer-shaped tool. It measures water at 0 and the fermented wort at ~5. Assuming him to have a regular hydrometer, I did not take a Brix reading of the OG.

It is a pilsner (100% German Pils, double decoction) and it is fermenting using WY2278 (Czech Pilsner). The basement has been around 47-50 deg the last couple of weeks, which is at the very low end of the fermentation temp for 2278.

He says there were some bubbles on top, the beer was pretty clear, and that he didn't notice bubbling in the air lock.

Questions then are (1) Is there any way to reliably convert his 5 Brix reading to SG? and (2) is this beeyotch finished? And I suppose (2b) if it's not, should I just wait it out or do something to make it keep going?

Thank you for any help or advice!
 
There are plenty of brix <-> specific gravity tables out there. Here is one:

http://www.fermsoft.com/gravbrix.php

Here is another with potential alcohol:

http://www.apple-cider-vinegar-benefits.com/hydrometer.html

I know you said its not a refractometer, but you need to remember that if you do get one (which I HIGHLY recommend) is that you need to use a special calculator to find the actual final gravity. The alcohol in the fermented wort affects the refractive index which means you can't use the tables like you can with floating hydrometers. Here is the one I use:

http://www.onebeer.net/refractometer.shtml

Don't use the onebeer.net link if you are using a floating hydrometer.
 
Unless you are making a high gravity brew, say 16 Plato or above, Brix is equal to Plato for estimation purposes. So a 5 Brix is a 5 Plato. Covering Plato to gravity and gravity to plato is just division or multiplication by 4. To convert SG to Plato just divide the last 2 digits by 4 (1.048 SG or 48/4 = 12 Plato). To convert Plato to SG just multiple by 4 (5 Plato X 4 = 20 or 1.020 SG). I would let it ferment a little longer if it were me. Lager yeast are slow fermenters and it is cool. Nothing wrong with being patient here.

Dr Malt
 
Sweet. I appreciate all the information guys.

So, my 1.040 lager is down to ~1.020 in ~3.5 weeks. Is this typical of the Czech Pils yeast? Cool temperatures probably mean slower fermentation, but at what point should I become concerned with the yeast becoming dormant and having a stuck fermentation? If I don't see any gravity drop over the next week or so, what is a good course of action? Warming? Adding yeast nutrient and swirling? (Already had him swirl the carboy to rouse the buggers). Sorry for all the questions, it's my first lager and it's frustrating not to be there to deal with it in person--I just want to have some answers when I talk to him on the phone :)
 
Unless you are making a high gravity brew, say 16 Plato or above, Brix is equal to Plato for estimation purposes. So a 5 Brix is a 5 Plato. Covering Plato to gravity and gravity to plato is just division or multiplication by 4. To convert SG to Plato just divide the last 2 digits by 4 (1.048 SG or 48/4 = 12 Plato). To convert Plato to SG just multiple by 4 (5 Plato X 4 = 20 or 1.020 SG). I would let it ferment a little longer if it were me. Lager yeast are slow fermenters and it is cool. Nothing wrong with being patient here.

Dr Malt

These numbers do not take into account the alcohol correction to properly figure your FG. This is fine for figuring your OG. I come up with 1.007 as your FG. This is using Beersmith and the online calculater from onebeer as posted above. Also 1.040=10 brix.
 
These numbers do not take into account the alcohol correction to properly figure your FG. This is fine for figuring your OG. I come up with 1.007 as your FG. This is using Beersmith and the online calculater from onebeer as posted above. Also 1.040=10 brix.

Since the reading is taken with an old wine hydrometer, rather than with a refractometer, I don't think one has to apply these corrections, right? It has to do with alcohol scattering light differently? Or is Brix a strange scale without a linear relationship with density/gravity? I may be way off here....
 
You are right, you do not need to correct for alcohol when using a hydrometer.

If you were using a refractometer then the alcohol would change the index of refraction of the fluid and you would need to use a calculator meant for refractometers.

You are about 1.020 and its not done fermenting.

Brix is a linear scale just like the rest of them.
 
Since the reading is taken with an old wine hydrometer, rather than with a refractometer, I don't think one has to apply these corrections, right? It has to do with alcohol scattering light differently? Or is Brix a strange scale without a linear relationship with density/gravity? I may be way off here....

Yes you are correct, I was thinking refractometer not a brix hydrometer.
 
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