OG/FG conundrum

How to get most out of brewing with your Braumeister? Help others and share your tips/best practices.

OG/FG conundrum

Unread postby royco » Sun Nov 23, 2014 8:06 pm

I regularly end up about 5 points low on OG, but then also get about 5 points lower on FG, so ABV is spot on. Is there an obvious reason, or would specific recipes be required to analyse this?
royco
 
Posts: 394
Joined: Thu Mar 06, 2014 7:48 am
Location: Durban, South Africa
Model: 50 litres

Re: OG/FG conundrum

Unread postby Dicko » Sun Nov 23, 2014 8:17 pm

Faulty hydrometer ???????

Incorrect mash efficiency in software but less likely than the above ?????

Incorrect water volume needed from software, possibly incorrect volume measurement ???

I would check the hydrometer first and go from there.
Measure distilled water at the specified temperature, usually 20 deg c or 16 deg c. This should be stated on the side of the hydrometer. Should read 0.00

:cheers:
The worst thing that can happen if I die is that my wife will sell all my brewing equipment for what I told her I paid for it
User avatar
Dicko
 
Posts: 1179
Joined: Tue Jan 21, 2014 8:25 pm
Location: Port Lincoln South Oz
Model: 20 litres

OG/FG conundrum

Unread postby Nesto » Sun Nov 23, 2014 10:26 pm

What software are you using to estimate OG and FG? Beersmith has a known error in calculating OG and FG causing errors of 3-5 points.
___________________________
Check out my brewing blog... http://www.sycamorecreekbrewing.com/
User avatar
Nesto
 
Posts: 790
Joined: Tue Jan 21, 2014 8:03 pm
Location: Northern California
Model: 20 litres

Re: OG/FG conundrum

Unread postby royco » Mon Nov 24, 2014 6:25 am

Interesting Dicko and Nesto. I use BS and didn't know there was an error. The OG is measured with a refractometer which has been calibrated, but maybe needs another check. I have two hydrometers; my old Coopers one and a glass precision model.
Actually they are pretty close in measurement. Next brew I will double check using the hydrometer for OG. It's just a small PITA having to cool the wort.
Thanks guys, it is good to get feedback from the experts!
royco
 
Posts: 394
Joined: Thu Mar 06, 2014 7:48 am
Location: Durban, South Africa
Model: 50 litres

Re: OG/FG conundrum

Unread postby Nesto » Mon Nov 24, 2014 3:20 pm

Sorry, usually around 3 pt error (4%) with BS...
viewtopic.php?t=531#p5161
And "underestimating" FG can be common in BS (getting lower than BS predicts), especially with step mashing and if your fermentation practices are really good (oxygenation, temp control).
___________________________
Check out my brewing blog... http://www.sycamorecreekbrewing.com/
User avatar
Nesto
 
Posts: 790
Joined: Tue Jan 21, 2014 8:03 pm
Location: Northern California
Model: 20 litres

Re: OG/FG conundrum

Unread postby BrauTim » Mon Nov 24, 2014 4:19 pm

During brewday I use a cheapo refractomer, which is not super accurate, to check things are progressing , it's quick and easy to spot if there is a problem with the mash using it, I do a spot check after 30 mins mash and can tell straightaway if there is a problem. The hydrometer gets used twice, at pre-boil and post boil because of the time it takes to cool the wort to get an accurate reading, but those accurate readings are needed to work out what your efficiencies are when inputting the figures back into Beersmith.

After nearly 20 brews I'm still tweaking the Beersmith numbers because variances on brewday always come into play, I reckon by 30 brews in I will need to tweak it less.

I used Leosardhino's spreadsheet predictor at theweekend also and found that worked out well when compared against Beersmith.
To brew or not to brew, that would be a stupid question !
User avatar
BrauTim
 
Posts: 595
Joined: Sun Feb 02, 2014 1:03 pm
Location: England
Model: 50 litres

Re: OG/FG conundrum

Unread postby royco » Mon Nov 24, 2014 5:56 pm

Thank you; actually had a look at leosardhino's spreadsheet and will try it on my next brew
royco
 
Posts: 394
Joined: Thu Mar 06, 2014 7:48 am
Location: Durban, South Africa
Model: 50 litres

Re: OG/FG conundrum

Unread postby royco » Fri Dec 12, 2014 7:11 am

Dicko wrote:Faulty hydrometer ???????

Incorrect mash efficiency in software but less likely than the above ?????

Incorrect water volume needed from software, possibly incorrect volume measurement ???

I would check the hydrometer first and go from there.
Measure distilled water at the specified temperature, usually 20 deg c or 16 deg c. This should be stated on the side of the hydrometer. Should read 0.00

:cheers:


Finally got around to checking my hydrometers with distilled water. Both read minus 3 points. Weird, because one is a cheap Coopers model and the other is a good glass type.
Now, where can I calibrate my distilled water? :roll:
It just goes to show, never have blind faith. I will get more distilled water from another source. If the readings don't change, this could explain my lower-than-expected gravity figures.
royco
 
Posts: 394
Joined: Thu Mar 06, 2014 7:48 am
Location: Durban, South Africa
Model: 50 litres

Re: OG/FG conundrum

Unread postby bruulog » Fri Dec 12, 2014 10:37 am

What was the water temperature?
I make my own copper/ss chillers (immersion) - 20l & 50l and counterflow (cfc)
bruulog.ee, Twitter: @BruuLog , FB BruuLog
bruulog
 
Posts: 168
Joined: Thu Aug 21, 2014 4:06 pm
Model: 50 litres

Re: OG/FG conundrum

Unread postby royco » Wed Dec 17, 2014 4:37 pm

Bruulog it was around 20°C. That was really stupid of me not to measure as a few deg could make a difference. It was a mild day so I just did the test at ambient. Will check again at calibrated temp.
royco
 
Posts: 394
Joined: Thu Mar 06, 2014 7:48 am
Location: Durban, South Africa
Model: 50 litres


Return to General / Tips and Tricks

Who is online

Users browsing this forum: No registered users and 5 guests