Inconsistent Gravities = Low ABV

[Quadrider]

Been brewing for about a year now. On my 4th batch... a grapefruit infused IPA extract kit from my LHBS. Estimated OG was supposed to be 1.065 with a FG of 1.014. My actuals were: OG 1.050 and FG of 1.012. Based on the estimated OG/FG my ABV should've ended up around 6.7%. When in all actuality, I'm now around 5%. Primary/Secondary was in a controlled environment between 66-68 degrees for 3 weeks.

Any idea where I went wrong? I followed the recipe to a T. Since my OG was so far off, The Only thing I can think of is that I used too much water when topping off the Wort into primary? I topped to exactly 5 Gal... From a 3 Gal Boil.

If it matters at all, I used The Catalyst for primary and secondary, and racked into a corny. The mason jar on the catalyst was a 32oz, and contained 90% trub on all three dumps. But I never topped the wort off post fermentation when swapping out the collection jars.

Thanks guys! This site is awesome!

 

[JordanKnudson]

Extract brews are notorious for producing bad OG numbers. The reason is that when you add top up water to the fermentor, the liquid stratifies instead of mixing homogenously. Thus, depending on which strata you pull the sample from, you often end up with a super high or super low OG reading. However, post-fermentation, it will have mixed properly.

With a kit, there is very little to worry about. You don't have to worry about conversion efficiency in the mash, like an AG brew, so as long as you added all the extract and hit the right volume in the fermentor, your gravity was more than likely spot on, and the low hydrometer reading was just a product of stratification of the wort.

 

[FVillatoro]

Sounds like you are diluting the wort with too much water.

If it's a 5 gallon extract kit, mark a place on the kettle/fermenter for 5 gallons (make sure it's accurate), and see where you are after the boil. If needed, add more water, mix thoroughly, take your sample, and proceed with the rest.

Happy brewing!

 

[JordanKnudson]

Sounds like you are diluting the wort with too much water.

If it's a 5 gallon extract kit, mark a place on the kettle/fermenter for 5 gallons (make sure it's accurate), and see where you are after the boil. If needed, add more water, mix thoroughly, take your sample, and proceed with the rest.

Happy brewing!

He mentions in his post that he followed the directions exactly and topped up to 5 gallons.

I guarantee that this was due to the poor mixing of wort and top up water. He got a bad reading, but if he did as he says he did, his gravity was almost certainly where it needed to be.

OP, remember, gravity is the measure of sugar in a given volume of liquid. Your sugar was predetermined--you simply added all of the extract. The recipe would have been designed so that that amount of sugar in 5 total gallons of liquid would produce the gravity that was listed on the kit instructions. Again, see my earlier post for the explanation of why your reading didn't reflect that.

 

[Quadrider]

The reason is that when you add top up water to the fermentor, the liquid stratifies instead of mixing homogenously. Thus, depending on which strata you pull the sample from, you often end up with a super high or super low

your gravity was more than likely spot on, and the low hydrometer reading was just a product of stratification of the wort.

Thanks for the awesome feedback Jordan! Much appreciated. To help alleviate this problem and receive a more concise OG reading, what do you recommend I do? Paddle in the extra 2 gal water top off? Add the 2 Gal. first and rack the finished wort on top of it? I'm not planning on jumping to AG anytime soon, so I'd like to figure out a way to resolve this issue moving forward. Thanks and Cheers! 🍻

 

[kh54s10]

Thanks for the awesome feedback Jordan! Much appreciated. To help alleviate this problem and receive a more concise OG reading, what do you recommend I do? Paddle in the extra 2 gal water top off? Add the 2 Gal. first and rack the finished wort on top of it? I'm not planning on jumping to AG anytime soon, so I'd like to figure out a way to resolve this issue moving forward. Thanks and Cheers! 🍻

Take the concentrated wort, add your top up water, Shake the living bejeebers out of the wort to aerate it. Then take your reading. It it seems off shake some more and take another one. With extract and top up you will never be 100% certain that you got it 100% mixed. If in doubt go by what the instructions said it should be.