FG lower than pre-boil gravity - WTF!

OK, I am really confused right now and I cant find anything on the forms (from what I searched under). I just brewed a wet-hop cascade pale ale. My pre-boil gravity was 1.044 taken at 138 degrees. The hydrometer temp correction calculator I use,
(http://hbd.org/cgi-bin/recipator/recipator/hydrometer.html),
corrected this to to 1.059. My expected final gravity was at 1.052, so I expected to completely overshoot that. Well that didn't happen. I boiled for an hour (normally do a 90 min boil) and took my FG reading expecting a 1.064 +/- and got a 1.052 (after correcting for temp). This makes no sense at all to me. I checked the hydrometer in plain tap water after I got this reading and it checked out at a perfect 1.000. (I know I am supposed to check it in distilled water but the water in Tahoe is pretty soft and always checks out at a 1.000)

I have brewed a lot over the years and consistently brew a batch a week to keep the pipeline full and I have never, ever had a final gravity reading be lower than the pre-boil gravity. Does anybody think that this could be caused from using the wet-hops? Did they absorb some of the sugars that dry-hops would not? Thats the only thing I can think of right now as this just does not make any sense. Please shed some light on this for me.

Wait, I didn't drink a beer while brewing today. Maybe the beer gods got me back for the huge mistake. Usually the first rule is to drink a beer while brewing, preferably a homebrew!

I'm confused, you mean original gravity? You took a pre boil reading of 1.044, boiled for an hour. Took a reading and it was 1.052? What reading did your cooled wort have? I'm thinking there was just a messed up sample somewhere. Also what was your grain bill, target OG etc?

I took a gravity reading after I finished with my sparge and collected all of my runnings and that read 1.044 at 138 degrees. I corrected the reading using the online calculator and found a pre-boil reading of 1.059. I do this every session and never had this happen. Grain bill was really simple:

2-Row - 45.5%
Maris Otter - 45.5%
Victory - 9%

My expected pre-boil gravity according to beersmith should of been a 1.044 but I am pretty sure thats after I correct for temp. Maybe its not and thats where I am getting this confusion. I have always assumed it was after correcting for temp. My target FG should of been 1.052. So I hit my numbers according to the beersmith software. I just started using beersmith but every batch I have done so far with it (10 batch's) I ended up with a slightly higher FG compared to OG.

Maybe this is where I am having an issue. If I don't correct for temp, my numbers are dead on. I always correct my gravity readings based on temp then compare that to my data as its just a habit to correct the hydro readings.

Remember that even with temperature correction tables, any SG sample over about 90 degrees is inaccurate- so inaccurate as to be worthless. Next time, cool the same to 90 degrees or less, and then take the reading and use the correction software or tables to correct it.

I will try that next time. I was not aware of that. I always thought I could correct using those charts at any temp. I bet my pre-boil gravities are all over the place then as I usually take my pre-boil gravity between 125 and 150 prior to lighting my burner. My FG's are always on-point with my expected efficiency, as this one was, but those are taken at around 70 - 75 degrees and usually only correct up a point or two at most.

Thanks for the replies!

TahoeRy said:

I will try that next time. I was not aware of that. I always thought I could correct using those charts at any temp. I bet my pre-boil gravities are all over the place then as I usually take my pre-boil gravity between 125 and 150 prior to lighting my burner. My FG's are always on-point with my expected efficiency, as this one was, but those are taken at around 70 - 75 degrees and usually only correct up a point or two at most.

Thanks for the replies!

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For future reference, FG is Final Gravity, meaning the gravity after fermentation. You are measuring OG or Original Gravity after the boil. I highly recommend a refractometer for Pre/Post-Boil Readings. It requires a few drops and cools down much faster. You can find a halfway decent one on Amazon for ~40 bucks.

Duh.... Wow you got me on that one. Total foot in the mouth. You are correct. My title is kinda obvious right. My FG better be lower than my pre-boil gravity. I guess I was so perplexed by my issue half my brain shut off. I am glad I at least got some helpful advice that I think will give me more of an accurate gravity reading. For a guy that's been brewing for 16 years you think I would of instinctively known not to type FG for my OG. Oh well. Funny, I didn't even notice it until you mentioned it.

I will use a hydomter, fill the tube and stick it in the freeze for a bit while the wort comes to boil, in about 15 minutes the sample will usually cool to below 95 and good to read.

I'm not a fan of adding dME but I will boil longer to get my post boil OG and just have a little less beer if necessary.

Yooper said:

Remember that even with temperature correction tables, any SG sample over about 90 degrees is inaccurate- so inaccurate as to be worthless. Next time, cool the same to 90 degrees or less, and then take the reading and use the correction software or tables to correct it.

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Been brewing a while, first post here.... I'm kinda confoozed.... this is the first time I've heard of the gravity reading being inaccurate over 90*. So, whyfore the tables/calculators give the numbers? I thought that was the point of the tables/corrections calculators? Understand, I'm just trying to figure it out, since I take constant readings, pre-boil, post-boil, as soon as I get the wort in the fermentor I'm checking, then when the Krausen starts to fall, I start checkin' n tastin'.....and when I'm not doing stupid things like sparging with water at the completely wrong temp, or adding a gallon more water than I'm supposed to... I usually hit my numbers pretty close. (at least now...lol...a while ago...yeah, not so much)

Always learn, right. I've been brewing for awhile and thought the same thing about gravity. Temps didn't matter as long as you adjust. Such is life - never stop learning.

TahoeRy said:

Always learn, right. I've been brewing for awhile and thought the same thing about gravity. Temps didn't matter as long as you adjust. Such is life - never stop learning.

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yep....it's not a good day til I learn somethin' new...... So, is good day
'course it blows the fuggle outta my whole system, but, I'm ok with that. Maybe it's an excuse to buy that new kettle I been eyein....