FG higher than OG 3 weeks later

[howe940]

Hi, I'm after a bit of advice as I'm new to brewing. I've followed a all grain stout recipe the problem is my FG has recorded 1060 which is higher than my OG 1050 after 3 week in primary. What have i done wrong? Can this be fixed?

 

[schmurf]

The fix would be to do another reading, it's clearly a misread of the FG. Do you use a hydrometer or a refractometer?

 

[Coastalbrew]

Are you using a hydrometer or refractometer to take your readings? Refractometer readings must be adjusted in the presence of alcohol. I suggest retaking your readings with a hydrometer. Otherwise you can use an adjustment calculator like the one on Brewer's friend to adjust your refractometer reading.

 

[1HW]

Did you see signs of fermentation, like a krausen or a bubbling air lock? If so, then your FG will be lower than your OG, and you should redo the FG reading as @schmurf and @Coastalbrew suggested. It's possible you missed a zero in the FG reading.

 

[howe940]

Hydrometer. Ive tested again and FG is 1022. So it looks like I've getting a 3.6% abv stout should have been 6%. To be honest I rushed in and kegged before reading hydrometer. I suppose ill learn.

What should have of done to increase volume?

 

[1HW]

Ok, so you have a Session Stout. The ABV isn't the most important thing to be concerned with when you miss your FG. The bigger issue is that you could have an overly sweet beer (or an unbalanced beer relative to bitterness) because there are unfermented sugars in the wort (i.e., the yeast didn't finish the job).

There are a number of things that influence your original gravity and the final gravity. The first question you should ask is whether you hit your OG as this is a measure of your beer's potential ABV. Whether you hit this target will depend on a number of factors such as whether the grain crush is too coarse, the temperature that you mash at (mashing at the lower range generally gives you more fermentable sugars), how you sparge, etc.

FG is influenced by the health of your yeast, how much yeast you pitch, the type of yeast you use (some yeasts eat more complex sugars, others eat the low hanging fruit and call it good), the temperature at which you ferment, etc.

If you post your recipe, including the yeast, amount, and fermentation temps, I think the kind folks here should be able to help troubleshoot.

 

[Coastalbrew]

Also post your process information. What was your mash temp throughout the mash? What was your cooling process and what temp did you pitch the yeast at? How long did you wait before transferring to the keg? Etc...

 

[howe940]

Thanks please see below
4000g pale ale malt
400g Crystal malt
400g chocolate malt
450g rolled oats
60g Golding pellets
12g classic English yeast

Mash
Temp 67c, length 60min
Boil
60mins

Dropped temp to 23c as recipe stated
OG 1062 (I followed everything spot on but got a 1050 reading).

Pitched yeast and sat in primary for 3 weeks at 20-22c

This should have been 18-20 but I couldn't keep temp down.
FG 1016 (I achieved 1022)

 

[Coastalbrew]

What was your overall batch size, how much beer did you make? Also did you monitor your mash temp throughout the mash, and if so, was the temp constant it did it change during the mash?

If the temp increased during the mash you could produce a less fermentable wort which would account for the higher FG.

 

[howe940]

It turned out to be 20 litres. Temperature was pretty constant throughout mash, dropped once by about 3 degrees and I brought it back up to 67c.
Wort started bubbling quite a lot for say 36 hours and then very sporadic for the rest of the 3 weeks. I didn't see any activity for the last 3 days so assumed it had finished.

 

[Coastalbrew]

What was your mash technique? Brew in a bag, cooler, etc?

All in all It sounds like everything went reasonably well. Fluctuations in mash temp can effect the fermentability of the wort. Also pitching more yeast at a cooler temp might have helped as well. Typically you want to pitch the yeast at the coolest temp, keep it at that temp for the first few days and then let it slowly warm a few degrees for best results. So for example, pitch the yeast at 18 C, hold the temp there for 3-5 days and then let it rise to 22-23 to finish the fermentation. Try not to let the wort cool down during fermentation.

Extra volume in your batch will reduce the og, though only by a few points, but keep in mind the published numbers in a recipe are just the expected targets. They are not actual statistics. Everyone's systems and processes are different and your results will vary. The more experience you get with the process on your system the more you will know what to expect and the better you will become at tweaking a recipe to get the numbers you want.

It sounds like this batch has given you a nice session beer and a good start in learning the fun of all grain brewing. Chock it up to learning and enjoy a few tasty brews.

Cheers!

 

[howe940]

Thanks for all the good advice, i was starting to worry i had ruined it. Something to learn from i suppose.
Thanks again

 

[IslandLizard]

3 other reasons your OG came out as 1.050 instead of the recipe's projected 1.062:

• (Too) coarsely milled grist
• Too much dead space in your mash vessel / Insufficient draining of mash tun
• Insufficient sparging

Or a combination of those. Look at your system and process and find out if any of those could be the cause, and fix them for next time.

So your 1.050 OG (projected was 1.062) went down to an FG of 1.022 (projected was 1.016)
Alcohol By Volume ABV Calculator - Brewer's Friend ==> 3.6 % ABV
You still made beer!