Constantly finishing under my FG

So I only have 5 batches of extract brewing under my belt. And I am constantly finishing under my suggested final gravity. Is there a reason that this would be happening? I have been right on my SG. I usually end up with a hair under 5 gallons come bottleing time. I do 2.5 gallon boils and top to 5 gallon in the carboy.

My fermenting Temp is a constant 65 deg, and put my yeast in 90 deg water 15 minutes before pitching, stirring 5 minutes before. I shake the living hell out of the carboy before pitching, probably for 5 minutes (until I get so tired i can't do it anymore)

I ferment in a 6.5 gallon glass carboy for 6-7 Days, then switch to a 5 gallon glass carboy for 10 -14 days.

latest example is a hefe that was supposed to finish at 1.016 and it finished at 1.006.

I was just looking for some input from you guys as to what could be the reason for such low finishing gravity? I mean more alcohol couldn't be a bad thing right?
I have 3 hydrometers and they are all giving me the same reading so it's not that.

Which tool do you use to predict your FG?

nilo said:

Which tool do you use to predict your FG?

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beersmith, and my local homebrew also works it up for me when i give him the recipe

Well, it sounds like you are getting an accurate reading. And most people get a higher FG on extract beers than they like, so if'n I were you, I'd be happy and just plan the OG to account for a lower than usual FG.

Homercidal said:

Well, it sounds like you are getting an accurate reading. And most people get a higher FG on extract beers than they like, so if'n I were you, I'd be happy and just plan the OG to account for a lower than usual FG.

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Oh by no means is this a complaint thread I was just wondering if there was a reason for it?

It would help if you could post the last two recipes that you had the issue, so we could plug the numbers in other tools and see what comes out. Please include your OG and FG's, predicted and real. Also add mash temp if all grain.
Also, if you are doing all grain, your mashing temp can have a big impact in your FG. If you plug 155F in the tool and your actual mashing temp is 150F, due to quick temp drop of your mash tun or inaccuracy on your temp measurements, that can drive your FG to much lowes numbers than expected.

OK, just saw you are doing extract, so never mind on the mach temp thing.

Yeah, I think you would really need to look at your OG to begin figuring this out.

Why are you putting your yeast in 90F water before pitching? If you're hydrating the yeast, it doesn't have to be 90F. In fact, it's better if the water is room temp.

Have you calibrated your hydrometer? They are pretty notorious for being off.

JohnnyO said:

Why are you putting your yeast in 90F water before pitching? If you're hydrating the yeast, it doesn't have to be 90F. In fact, it's better if the water is room temp.

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There is a statement at this forum from someone that works at a dry yeast company saying the ideal is to re-hydrate at 105F, mix well for 5min, then pitch. Use only tap water, no sugar or DME or wort, just tap water.
That is the procedure I start using about a year ago and has proven to work.

Check hydrometer calibration. 1.000 in distilled water @ 60 degrees. You may also want to calibrate to multiple points. Check this BYO article

Bithead said:

Check hydrometer calibration. 1.000 in distilled water @ 60 degrees. You may also want to calibrate to multiple points. Check this BYO article

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I have done so, and all 3 of mine are dead on. I have talked to other brewers in my immediate area and they say that there beer always comes in under as well...maybe it has somehting to do with the water?

Rehydrating at 90F is the norm. Yeast LOVE that temp! Fermenting wort at that temp is not great though. It's best to start them at 90ish and drop the temp naturally while waiting for the yeast to absorb the waiter, then pitch. But we're splitting hairs here.

I would be curious what your recipes were, but my gut instinct is that it's not going to tell us anything.

Certain bacteria can cause a beer to lose points, but usually over a bit of time.

Do you check your OG before pitching? AND COMPENSATE FOR TEMPERATURE?

Do you add sugars?

Do you knock carbonation out of the sample when you read it? (Bubbles from fermented wort CAN raise a hydrometer in the sample, especially if it's cooler. This should give a higher FG reading though IIRC...

I do check SG but I do not compensate for Temp..... since I chill my wort to 78 and then add another 2.5 gallons of 65deg water i figure it's around 70.

when I check my SG I pour a sample into a plastic cup and then pour into my cylinder, then I clean up and test about a 1/2 hour later once it is settled.

I was a biology major, so I know my way around a lab, being sanitary, proper procedures and what not.

but I seem to get the same answer on here that I do from everyone I talk to which is:

"Who cares? be happy about it"

I was just curious if finishing out lower was a common occurance and if there was a common cause to to?


I appreciate everyones responses. This site is a gold mine of knowledge. I have spent endless hours of reading threads on here and as a result I am brewing some pretty tasty (and strong) beers.

Yeah, I hate to ask what might be very obvious... but you're correcting the SG to your hydrometer's calibrated temperature, right?

emjay said:

Yeah, I hate to ask what might be very obvious... but you're correcting the SG to your hydrometer's calibrated temperature, right?

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well it's calibrated at 64 deg

my initial readings are taked at 65-70 deg and final readings are taken at 65 deg.

I do not see any need to take into account 1-5 deg difference when I am seeing such a huge difference in FG. if I were withing .004 i wouldn't have givin it much thought but I am constantly .004 - .01 under.

and like I said in my OP I have 3 hydrometers and they are all saying the same