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Low OG in NB kits

I have brewed two NB extract kits, the Tongue Splitter pale ale and the Chinook IPA, and both times the O.G. has been below what the recipe kit suggests. I’m new to brewing so I didn’t think I’d hit it right on the mark, but I’m concerned because in both cases the OG has been 10 to 20 points lower than what it should have been. I didn’t divert from the directions and am curious if this could be fixed by utilizing a full volume boil…any suggestions?

I’m assuming that you did a partial boil and topped off with water. Did you take your specific gravity sample without mixing everything together? If you didn’t, your sample could be more watery than you want. I brewed an ESB last week and I was 10 points below what I should have been. I mixed the wort and took a second sample. Still 4 points under but I think that was because I topped to 5.5 gallons rather than 5.0. With an extract kit, I wouldn’t worry a lot. RDWHAHB!

Have you tested your hydrometer to make sure it’s accurate? Short of forgetting to add ingredients or not finishing with the correct volume, extract kits should be pretty much dead on.

Playing around with the above calculator, the difference between 5g of a beer that should be 1.060 and is at 1.055 is .65g.

It’s possible the each batch of LME and/or DME has a variable in the expected OG, but I wouldn’t suspect it to be 10-20 points.

The most likely answers are:

  1. you hydrometer is not accurate. A couple years ago my local club did a hydrometer test day. We had a lab grade thermometer and distilled water. I also made up a salt solution based on saturation levels and diluted it down as accurately as possible to make a 1.050 solution. There was only 1 or 2 out of 15-20 that did not need to have some nail polish (mine needed lot’s) to make it read properly. I think 1 needed to have some glass filed off the make it lighter.

  2. your water volume is off. That .5g can skew the reading by 1.005.

  3. If you do a partial boil and top off with water, you don’t have a good mix of the sugars before taking they hydrometer reading. Not a issue. As the day goes by the sugar will go into solution and the yeast will find it and make beer.


I just did the math to find the volume of one of my fermenting buckets…at the 5 gallon line mine is actually 5.4 gallons. Its a possibility if your going by the printed marks on a bucket.

There could be several reasons that you are getting off readings on your OG. The most common is that the wort was not mixed fully at top off. It is pretty difficult to get the wort mixed well. Your hydrometer may be inaccurate. Also incorrect volumes would skew the OG. Another would be that the directions were not followed properly.

I would say that your OG was OK and that you will end up with a very good beer.

These are all really good answers…thanks for the insight. I’m gonna give myself the benifit of the doubt and assume that the wort wasn’t mixed properly. Happy brewing!

The purists may demand my execution for this…but I quit taking OG and FG readings after my 2nd batch…I’m an extract brewer…I ferment for 3 weeks (watching for fermentaion activity) and then bottle…Not very scientific or technical, but the beer is great! I love this hobby and I love the fruits of my labor!

anyone have some rope? :lol:

I never had an issue with their extract kits during 3+ years of extract brewing so long as I:

  1. didn’t add to much water at end of boil
  2. heated the extract jugs in a hot water bath prior to adding to my pot to ensure I got all the goodness out of the jug. I also rinse the jugs with hot (from the pot) water too, pouring remaining goodness into the pot.

Assumption being hydrometer was reading properly.

FWIW, I recently stopped taking readings too as my AG system/routine is now pretty dialed in. Estimated ABV works for me. I’ll probably do readings on “new” recipes though.


Being 10 to 20 points off of OG, what temperature was your wort when measuring?
My first batch I was parnoid and boiled my top off water before hand, and let it cool for several hours. Idiotic me, I kept it on the back of the stove I was boiling wort on…hence it warmed back up to about 95-100 f.

So when I topped off and mixed, my sample was about 20 degrees warmer than it should be…my targeted gravity was 1.043…only measured around 1.020.

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