I think i got a wrong OG reading

[jjwilkes83]

Hi all I need help I'm new to all this brewing my own ale and everything and when I tested my brew after 24 hours I had a hydrometer reading of 1.004 stored at 24C however I pretty sure I may of made a mistake when taking my OG reading. How can I find out the alcohol content now? Please help

 

[woozy]

You should take the hydrometer reading before or at the time you pitch the yeast; not after 24 hours. To figure out what your original gravity *was* enter your ingredients into a brewing calculator. (And here's another.)

 

[fuzzy2133]

The alcohol content will not be know until the yeast finish and you hit Final Gravity (FG)

The formula for ABV% is: ABV= 131 (SG - FG)

 

[jjwilkes83]

I got the standard coopers real ale I took the reading before adding yeast as instructed and I got a reading of 0.990 but compared to all other posts I've seen this is really low I've seen people stating that their OG is around 1.040 as this is my first time I'm getting worried I've messed it up

 

[jjwilkes83]

I got the coopers real ale kit and I took my OG reading before adding the yeast as per instructions how ever it was 0.990 I have seen over posts which state theirs were around the 1.040 mark a this is my first time I'm worried I've made a mistake mine seems really low

 

[Weizer]

I got the coopers real ale kit and I took my OG reading before adding the yeast as per instructions how ever it was 0.990 I have seen over posts which state theirs were around the 1.040 mark a this is my first time I'm worried I've made a mistake mine seems really low

Are you sure you read it correctly? 0.990 is less than water..You should put your hydrometer in a glass of room temperature water and take a reading. It should read 1.0.

 

[woozy]

You are misreading the hydrometer. If the coopers kits says the OG is 1.040 and you added the correct amount of water and sugar[~] then your OG *was* 1.040. So that's that.


So you have two weeks to practice reading the hydrometer. 0.990 is impossible because a reading of less than 1.000 means the wort is *less* dense than water and as sugar makes liquids *heavier*, only alcohol makes liquids lighter. And you didn't start with any alcohol.

Take a measure with just water. That should be 1.000.

Try mixing one oz (in weight) of table sugar into one cup of water. (Stir well to make sure it dissolves). That should read 1.046[*].


If your hydrometer is consistently off then your hydrometer is poorly calibrated (it happens) and you'll need to adjust your reading. Otherwise try to notice if you hydrometer is sticking to the side of the sample jar. Try spinning the hydrometer. Many people say they take samples in the tube the hydrometer came in, but I have found I've never been able to as it is too narrow for the hydrometer bulb to float freely.

Some hydrometers come with multiple scales. Perhaps you are reading a wrong scale.

Hopefully we'll get it figured out in the next two weeks.

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[~] I actually don't know whether the Coopers kit required sugar. Some do and some don't. If it didn't don't worry. In either case, if we assume you added the right amount of sugar and/or water your o.g. should be set in stone.


[*] FWIW Rule of thumb: one pound of sugar in a gallon of water has a reading of 1.046 or has 46 gravity points. (A gravity point is to subtract the 1 and multiply by 1000). We say sugar has 46 points/pound/gallon or 46 PPG. A PPG means a substance (a sugar, a grain, an extract, etc.) has enough sugar so that one pound of the substance in a gallon of water will raise the specific gravity by 1 point. This is very useful in calculating your brews and measurements.

Your coopers kit has a specific PPG and so by adding it to the correct amount of water (and sugar, if nesc.) we *know* your OG had to be 1.040 (assuming we trust what Coopers told us).

As a cup is 1/16 of a gallon and an oz (weight) is 1/16 of pound. We know one cup of water mixed with one oz. of sugar will also have a specific gravity of 1.046.

 

[jjwilkes83]

Is there any way I can work out what % when finished ?

 

[jjwilkes83]

Many thanks that has helped explain it

 

[kh54s10]

Make sure you are reading the hydrometer correctly and that you are sampling at the temperature for the hydrometer (usually about 60°F) Then take your final gravity readings 2-3 weeks from now, take one wait until the 3rd day for the second. If they are the same, fermentation is finished. If you used all the ingredients in the kit and ended up with the right volume you can use the kits suggested OG. Use the formula already given or plug the gravities into an online ABV calculator. (a search will find several)

Given any error factors your ABV will be very close. Other than that just forget about the alcohol level and enjoy the beer.

 

[woozy]

Is there any way I can work out what % when finished ?

Yes. As fuzzy2133 pointed out earlier:

Alcohol percentage by Volume = 131 x (Original Gravity - Final Gravity)

Ex. O.G 1.040, Final gravity 1.008. Difference is .032. 131 x .032 is 4.19%.

That's by volume. I *think* to figure alcohol by *weight* you multiply the difference by 125. But I'll have to research that.
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Some hydrometers have an "alcohol potential" scale. An o.g. of 1.040 corresponds to an alcohol potential of 5.24%. This means that if every scrap of sugar were converted to alcohol it'd be 5.24% alcohol. A f.g of 1.008 corresponds to 1.05% alcohol meaning that's how much *potential* alcohol is left unconverted. Subtract the two and you get 4.19% and that's how much actual alcohol was actually converted.

But using the formula is better simply because the scale on the hydrometer is probably better.

My hydrometer has a third scale called a "balling" scale. I have no idea what this measures nor if it's linear to the specific gravity scale. I do know that for my second brew I read it instead of the specific gravity scale my o.g. was completely wrong. Haven't met anyone else who made *that* mistake but I keep looking.