OG and FG frusteration

I just started my second batch ever. I went from the Mr. Beer to the True Brew kit. It was an obvious difference in quality. I did an IPA kit because I love IPAs. I followed the directions down to the letter and was satisfied that I made no mistakes. The only difference is that I added and alcohol booster also.

Upon taking my OG is said that it was 1.036. The kit stated that the OG should be near 1.051. Since I followed the directions, I did not worry. One week after fermentation, my FG reading was 1.022. After running the OG and FG through and alcohol calculator, my % came out to be 1.84%.

This seems really off to me and I can't figure out why. Upon adding the yeast, within 12 hours I had really strong activity and it almost blew the air lock right off. It kept bubbling through the airlock. With all of the activity I am quite certain (with my limited knowledge ahahahah) that the alcohol content HAS to be higher than that. This leads me to believe that my OG reading was off.

I'm just wondering if anyone can help me shed some light on the situation. I intend to let the batch keep fermenting a few more days than the minimum 1 week. Any and all input is welcome

What was the temp the wort when you took your OG reading?

aha! there-in lies the missing link! Im not sure. I let it cool but did not take it at any specific temp. Will this ruin my beer? I know it was higher than 70 degrees and under 100

Your top off water was likely not mixed completely with the wort. Therefore when you took your hydrometer sample it was diluted by the water on the top. Its nearly impossible to screw up the OG on an extract batch unless you add too much or too little water. Its safe to assume as long as you added all the malt extract that you did hit 1.051.

I betcha a million dollars that your og was really what it was supposed to be in the recipe....

Here's the answer we give about 10 times a day here,

It's a pretty common issue for ANYONE topping off with water in the fermenter (and that includes partial mashes, extract or all grain revcipes) to have an error in reading the OG...In fact, it is actually nearly impossible to mix the wort and the top off water in a way to get an accurate OG reading...

Brewers get a low reading if they get more of the top off water than the wort, conversely they get a higher number if they grabbed more of the extract than the top off water in their sample.

When I am doing an extract with grain recipe I make sure to stir for a minimum of 5 minutes (whipping up a froth to aerate as well) before I draw a grav sample and pitch my yeast....It really is an effort to integrate the wort with the top off water...This is a fairly common new brewer issue we get on here...unless you under or over topped off or the final volume for the kit was 5 gallons and you topped off to 5.5, then the issue, sorry to say, is "operator error"

More than likely your true OG is really what it's supposed to be. And it will mix itself fine during fermentation.

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Yours was no different.

Most likely you added top-up water after the boil, then took your OG reading when it "looked" mixed. It probably wasn't, it's very tedious, and often unnecessary, to mix the jug long enough to thoroughly mix it up.

What was you target OG? Is it the 1.051, or something bigger because of the boost? Probably around 1.060, giving an ABV of close to 5%. If you added all the extracts, you can pretty much assume that's what it was, regardless of the reading.

You should give it more time, anyway. One week isn't really enough.

ETA: the things people say, when I'm busy typing...

Well If I enter the correct OG into the alcohol equation the new % is now 3.81% that is much better. However, I did add an alcohol booster so that seems low. Is the % alcohol content likely to increase still? Should I leave it to brew longer?

Also, after adding everything to the carboy it is hard to mix it well through the narrow opening.


Thanks all btw, I love the quick input....this is the greatest forum ever!

Revvy said:

I betcha a million dollars that your og was really what it was supposed to be in the recipe....

Here's the answer we give about 10 times a day here,



Yours was no different.

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Exactly! This happened to me in my very first batch using the coopers kit and the beer turned out just fine. The alcohol calculation came out something like 1.5% because of the false OG reading. How did I confirm my suspicion? Made my mother in law drink half cup of it and she got drunk proving alcohol levels was just fine...

That is awesome! Im would be psyched If I could get the % to come out around 6-7%. Letting it ferment a while longer should help that right?

IPANY said:

That is awesome! Im would be psyched If I could get the % to come out around 6-7%. Letting it ferment a while longer should help that right?

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There is only so much that can be fermented into alcohol. Any extra time on “fermentation" after that helps with conditioning the wort and settling down unwanted sediments. Most ales stop alcohol conversion in about or before 1 week.

Here is one of many I assume, calculators to correct the hydrometer reading for the temp the reading was taken at, http://dd26943.com/davesdreaded/tools/convert.htm. It's easy nuf to do manually but this may be more accurate. I avoid the topping off problem by boiling around 5.5 gallons water and end up with 5 gallons but one needs a big pan to do this. I also put in a bubbler to areate the wort before yeast is pitched and sealed up. This might assist in mixing in top off water.

An easy rough ABV calculator is (OG-FG) x 131.

So, in your case: (1.051- 1.022) x 131= 3.8% ABV. Of course, at 1.022 I doubt it's done. It should finish at 1.014-1.016 or so I'd guess. Also, with the alcohol booster, it should be higher than the named OG in the recipe.

If it tastes great, that's the important thing!