Hydrometer reading/SG mystery

[fimpster]

I’m wondering if any of you have run into this problem, or if it’s even a problem at all? A couple of weeks ago I brewed a Cream Ale and BeerSmith estimated my S.G. at 1.043 and QBrew estimated it at 1.044. I ended up with a reading of 1.038. Then a week ago I did a wheat beer. BeerSmith estimated it at 1.047 and QBrew at 1.049 but again I got a reading of 1.038. By this time I thought my hydrometer was broken. I could see a tiny hairline crack on the bottom and I thought it might be taking on liquid or air and giving an incorrect reading. I couldn’t see any liquid inside, but my readings were way off, so I bought a brand new one. When I got home I checked back on the Cream Ale and with my new hydrometer got a reading of 1.016. Out of curiosity I tried the old hydrometer and it read 1.015, pretty close to the new one. Last night is when I really got confused; I brewed a Honey Pale Ale that BeerSmith estimated at 1.057 and Qbrew at 1.060, but both my old and new hydrometers took the same reading of 1.047. What is going on? I guess maybe my first hydrometer is just fine after all? All of the above S.G. readings were adjusted for temperature, so I know that’s not the problem, even so I don’t think that would cause a discrepancy of 10 points or more. Have any of you seen something similar? What could be causing the problem? Is it even a problem if my beer is just fine? I’m not going to worry too much about it, I’ll just relax and have a homebrew, but it is a mystery. Any feedback/advice is welcome.

 

[fimpster]

wow, no one has any ideas about this?

 

[loopmd]

I used my hydrometer on my very first batch, then promptly threw it away. I've made probably 250 gallons of beer since then and never used a hydrometer. (extract brewer...not all grain)

best thing I ever did.


Loop

 

[rod]

are you extract or all-grain?
if extract i can't explain it
if all grain - your efficiency could be less than that estimated in qbrew or beersmith. if this is the case - add some more grains.

 

[fimpster]

lol, great advice, loop. even though i too am an extract brewer (and an occasional pm) i have enough batches under my belt to know when to bottle without making any bombs, but in the back of my mind i couldn't let it go without taking a reading.

 

[loopmd]

I hear ya...it is kinda fun to see where you started and where you end up and then calculate your alcohol content....worrying about the numbers took the fun out of it for me, so I don't do it anymore.


loop

 

[david_42]

About 90% of what I use a hydrometer for is to check when the ferment is done.

Consistently low readings are most likely due to too much water. I'd check whatever you are using to measure volumes.

 

[fimpster]

ok, thanks. i have a fermometer on my 6½ gal carboy that i use as a 5 gal marker but maybe i do need to check how accurate it is.

 

[fimpster]

well, its not too much water. i checked both of my 6½ gal carboys and the 5 gal mark is accurate to within less than a pint.

 

[david_42]

A pint's not going to generate consistent 20% errors. You do indeed have a mystery. Is this a new problem?

 

[zoebisch01]

I'd chalk it up to global warming.

 

[cweston]

Did you use the same brand of extract for each batch? It's possible that the extract itself has a lower gravity value than it's supposed to?

Also, did these recipes have significant amounts of steeping grains? I thing the brewing software sometimes grossly over-estimates the amount of sugars extracted from steeping--steeping efficiency is usually only something on the order of 30-40%.

 

[fimpster]

i did use the same brand of extract on all batches. Coopers for LME and Muntons for DME. two of my last batches did have ½ lb of crystal malt and the cream ale had flaked maize. i know you really should mash maize to get any fermentables out of it so that may be a small bit of the problem. this afternoon i also tested both hydrometers with 60° water and both were dead on 1.000.

cweston, i think you're right. at this point i'm guessing that it is just the software miscalculating the S.G. my beer tastes great so i'll just let it remain a mystery.

thanks
~vin

 

[Ó Flannagáin]

Don't forget temperature. Hydrometers read accurately at 60, 70 or I think some are even 80F. It should say on the hydrometer. If your wort's temperature is higher than the accurate reading temperature then the reading will be low, like yours is. a 1.047 gravity would ready at like 1.040 if the temperature was 120 or so. Make sure to cool your wort completely before reading.

... I made this mistake with my all grain, to test my preboil gravity... FREAKED ME OUT.

 

[wild]

Have you tested your hydrometers for accuracy. Go here to calibrate.

Good luck,
Wild