I know I know Low OG

[Pi Kapp Beer Guy]

Ok so here it is I hate posting this because I have now been around long enough to try and search for the answer first. Well almost everyday i read about some ones low OG and its always well you probably didn't mix it well enough and got an incorrect reading. However I did a foil boil of about 6 gallons for 60 mins so i dont see how it could not be mixed. I boiled 3 lbs of Dried Amber malt extract mixed with the water from steeped .5 lbs of dark grains. I also did a late boil addition of 4lbs of Dried amber malt extract. Not to mention .5 lbs of malto dextrin. At the end of the boil i cooled for twenty minutes took the OG reading and got 1.038 after the adjustment for temp. I dont remember the temp i took it at but it couldnt have been much higher than 100F (i know bad record keeping) SO what gives? My Beersmith tells me even ruiling out poor efficiency the extract alone should be around 1.061. So is this right? Did I get an incorrect reading? As far as fermentation i did not have a good starter and it took three days to get going. A violent fermentaion later the airlock is still active 6 days after the first sign of Krausen. Any ideas?

 

[Bob]

None, frankly. I have no idea how you could have gotten such a low reading under those circumstances.

If you used extracts, however, you may rely on what your software tells you. It's not like your efficiency could be off. Well, Muntons or Briess's efficiency could be off, but that's highly unlikely!

Bob

 

[Yooper]

My experience is that at high temperatures, even with adjustments for temperature, a hydrometer is notoriously inaccurate. It should be cooled down to under 100 degrees (and then the reading adjusted for temperature) when you take an OG.

My belief is that your OG was in the 1.061 range. The sugars are present in the extract, and don't disappear. Since fermentation is still going on, you know that you had enough for the yeast to eat.

 

[mmb]

With extract there would only be two reasons why your gravity would be off.

You didn't add all the extract.

Or

You have too much water after boil and watered down your beer.

If you're sure about your volumes and process, no worries. The OG should be about where the estimate is. As Yooper said, 100 is pretty high. I take my sample and stick it in the freezer for 5 minutes to cool down.

 

[Bob]

I use a refractometer. No muss, no fuss. Sure, it's fifty bucks as opposed to ten, but...

 

[Pi Kapp Beer Guy]

Good call on cooling down my sample next time in the freezer for five minutes and i will be sure to do that. I did use Muntons extract but it would be hard for me to beleive it is off by that much so I am going to throw that idea to the side. As far as volume and procedure I am sure that all of the extract made it in there as well as the amount of water I used. So I'm going with the temperature I checked the wort was too high. As far as the refractometer, well it sounds good but in the article I read it said calculations needed to be made for measuring wort. I understand the equation for converting Brix to OG but what is the meassurement of error when recording gravities if they say each brewery can have its own equation for wort depending on the style of beer?

 

[Bob]

Um...what? Each style of beer has its own equation for...huh? Which article was this?!

The only time you need to make calculations is if you wish to convert °Plato to Specific Gravity. I'm glad you can use the equation; that's too much math for me. My records are all in °Plato, and to convert to SG I use a chart. Edit: Here is another chart in PDF.

I like the refractometer in the brewhouse because it makes life so much easier. Let's do the "how much convenience is worth" math.

1. Take a three-drop sample, place on glass, close cover, count 10-Mississippi, observe and record reading.

2. Take a graduated-cylinder sized sample, place in freezer, count to 300-Mississippi, float hydrometer, make mess, perform temperature-relative calculation anyhow because it's still not the calibration temperature, observe and record reading, clean up sticky spilled sweet wort (you do overflow your sample tube when you drop-and-spin the hydrometer, right?).

I've taken enough brewhouse gravities that, even if my time is worth minimum wage, my refractometer has paid for itself about seventeen times!

Bob