I have a question, I just did a brew with Northern Brewers Caribou Slobber. My OV came out at 1.050 not 1.053. It dawned on my that this is the first time I used an areation stone. After 20 minutes of pumping air in the fermenter, I dropped in my tilt 2 and then pitched the yeast. Wouldn’t the air in the wort lighten my OG? Making it lower?
OG question
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Firstly, 3pts is not really a lot. Also, does the Tilt calibrate to a calibrated hydrometer, calibrate to a known sugar solution? Just some quick thoughts. Was it an extract kit? If so, all the sugar that can be in it is in there.
But mainly, 3 points is not really a big miss.
But mainly, 3 points is not really a big miss.
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Did you end up with the right volume of wort? A little too much water would lower your OG.
Did you end up with the right volume of wort? A little too much water would lower your OG.
BrewnWKopperKat
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building on what @Rish said, an additional quart of water in a 5 gal wort would drop the OG from 50 to 53 (I can show the "gravity point" math if you're interested).
It could also be a difference in PPG estimates/actuals. If I use 36/44 for PPG for the LME/DME, I get an estimated OG of 53. If I use 35/43, I get an estimated OG of 50. (I can also go deeper on this math if you're interested).
And I'll agree with @balrog : 3 points (estimated vs actual) is not a big miss.
Yes, extract kit. But my question is, will the air effect the OG?
I get there is a lot involved, but will the air effect the OG?
No
BrewnWKopperKat
ʘ‿ʘ
I'll suggest "no" and suggest an experiment to confirm this. In a container where you can observe volume in 1 cup increments, fill the container with 2.5 gal of water. Run the aeration for 20 minutes At the end of 20 minutes observe the volume of water.
Also observe the amount of oxygen left in your tank. It will be less. A lot less.
On a different note… what kind of yeast? From Lallemand’s website for their dry yeast:
- Aeration is not required for the first pitch
Yeast is irrelevant, tilt took its reading prior to yeast. I will say that aerating made a huge difference with the dry yeast. It was bubbling within a couple hours.
BrewnWKopperKat
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What strain of yeast were you using in the batches you are comparing? Some strains of dry yeast start/finish fast, others can take a little more time.
If the air is constantly pumped through the water while measuring the OG via a swimming hydrometer like a tilt, then it will definitely lower the measured OG.
Once the air is turned off and no bubbles are passing through the water any more, the og will be normal again.
This is actually one of the suspected reasons why ships are disappearing in the Bermuda triangle. Methan eruptions creating small bubbles, lowering the gravity of the water up to a point where ships sink because they are too heavy to float in such a gas/water mix.
Once the air is turned off and no bubbles are passing through the water any more, the og will be normal again.
This is actually one of the suspected reasons why ships are disappearing in the Bermuda triangle. Methan eruptions creating small bubbles, lowering the gravity of the water up to a point where ships sink because they are too heavy to float in such a gas/water mix.
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Yes, active bubbling will affect something floating.
Dissolved O2 would not, I do not believe, affect SG measurably, at least using methods available to most home brewers; I'm sure @doug293cz could calculate it, but Da Mighty Google gave me this:
Dissolved oxygen is not going to decrease the density of water, so measuring dissolved oxygen is not going to help you. In fact, dissolved oxygen increases the density of water ever so slightly. Watanabe and Iizuk studied the effect of dissolved oxygen and other gases on the density of water, and measured an increase of 0.0022% per ppmw of dissolved oxygen:
"The Influence of Dissolved Gases on the Density of Water"
H. Watanabe and K. Iizuka, Metrologia, 21, 19-26 (1985).
ShieldSquare Captcha
So each 1 mg/L increase in dissolved oxygen will increase the density of the water by 0.0022%.
Dissolved O2 would not, I do not believe, affect SG measurably, at least using methods available to most home brewers; I'm sure @doug293cz could calculate it, but Da Mighty Google gave me this:
Dissolved oxygen is not going to decrease the density of water, so measuring dissolved oxygen is not going to help you. In fact, dissolved oxygen increases the density of water ever so slightly. Watanabe and Iizuk studied the effect of dissolved oxygen and other gases on the density of water, and measured an increase of 0.0022% per ppmw of dissolved oxygen:
"The Influence of Dissolved Gases on the Density of Water"
H. Watanabe and K. Iizuka, Metrologia, 21, 19-26 (1985).
ShieldSquare Captcha
So each 1 mg/L increase in dissolved oxygen will increase the density of the water by 0.0022%.
I was thinking of naming my kegerator the Bermuda Quadriangle (4 tap) cause after i put a beer in there it disappears.
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I have a lot of Bermuda bottles, now that you mention it....
I’m not comparing batches. My question was just that being that I aerated the wort before adding my tilt meter, would that change the OG while it was still full of air. Much like methane or hydrogen gas changes the density of the water over the Bermuda Triangle causing boat to sink
I will do this after my fermentation is complete.
BrewnWKopperKat
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To have a difference, there needs to be a comparison to something. Typically people compare different batches.
I understand that part of your question. I was just pointing out that the aeration may be an unnecessary step if using today’s modern dry yeast. That’s also what @BrewnWKopperKat is referring to about knowing that it affected the speed of the fermentation start. There’s no way to determine that unless there’s a comparison to a similar batch that wasn’t aerated. I digress and that’s a different topic than the original post.
And to your original question about OG… aerating the wort shouldn’t have any affect on gravity readings as long as the reading isn’t during the aeration process.
Unless you’re using lab grade equipment, I don’t think I’d get too much heartburn over a 3 point difference in measured gravity vs. predicted gravity… lots of different factors could make a couple points difference.
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Three points is nothing. Every batch of extract is not going to have the same amount of sugars. Only way to know what the SG if the extract you used actually was would be to see a Certificate of Analysis from the manufacturer (more than likely Briess).
If anything aerating the wort ensured a more accurate gravity reading. Whenever I did a partial boil with extract, the wort would stratify and my gravity readings would be way low because a disproportionate amount of the sugars were at the bottom of my fermenter.
Now most of the time I don’t bother with gravity readings when I’m brewing with extract.
If anything aerating the wort ensured a more accurate gravity reading. Whenever I did a partial boil with extract, the wort would stratify and my gravity readings would be way low because a disproportionate amount of the sugars were at the bottom of my fermenter.
Now most of the time I don’t bother with gravity readings when I’m brewing with extract.
redrocker652002
Well-Known Member
I don't have much more to add other than, if you only missed by that amount you should be ok. You will still have beer, and that is the outcome you want. LOL. I have missed by a few more than 3 once or twice and it still tastes great, so I don't think you will see any difference other than a bit of a ABV difference. Take that for what it is worth as I am a fairly new brewer myself.
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