Not Reaching Fg

[Damian44]

Hey guys. My last couple of batches have come up short of their FG. A Stout was supposed to drop to 1.012 but only made it to 1.017. I bottled it and no bottle bombs.

My current batch....

5.00 kg Pale Malt, Maris Otter
0.50 kg Crystal (Joe White) (72.0 SRM)
0.10 kg Amber Malt (22.0 SRM) Grain 1.79 %
50.00 gm Goldings, East Kent [4.80 %] (67 min) Hops 19.2 IBU
20.00 gm Goldings, East Kent [4.80 %] (30 min) Hops 5.8 IBU
20.00 gm Goldings, East Kent [4.80 %] (1 min) Hops 0.3 IBU
1.74 items Whirlfloc Tablet (Boil 15.0 min)
1 Pkgs English Ale (White Labs #WLP002) Yeast-Ale
25L

This one droped down from 1.040 to 1.020 after 7 days, but has not fell any further after 4 more days. It should finish at 1.012. Ive been rocking the fermenter as the yeast likes to drop out. What gives?

 

[mika]

Poor yeast health, too high a mash temp...myriad of things. Going to need a few more facts before the WAG's coming flying thick and fast.

 

[hoppinmad]

Hey guys. My last couple of batches have come up short of their FG. A Stout was supposed to drop to 1.012 but only made it to 1.017. I bottled it and no bottle bombs.

My current batch....

5.00 kg Pale Malt, Maris Otter
0.50 kg Crystal (Joe White) (72.0 SRM)
0.10 kg Amber Malt (22.0 SRM) Grain 1.79 %
50.00 gm Goldings, East Kent [4.80 %] (67 min) Hops 19.2 IBU
20.00 gm Goldings, East Kent [4.80 %] (30 min) Hops 5.8 IBU
20.00 gm Goldings, East Kent [4.80 %] (1 min) Hops 0.3 IBU
1.74 items Whirlfloc Tablet (Boil 15.0 min)
1 Pkgs English Ale (White Labs #WLP002) Yeast-Ale
25L

This one droped down from 1.040 to 1.020 after 7 days, but has not fell any further after 4 more days. It should finish at 1.012. Ive been rocking the fermenter as the yeast likes to drop out. What gives?

I have had the same thing occasionally with my heavier beers. I do persist in trying to get the ferment active again, but if it doesn't move for three or so days I consider it done.

I had an English Brown Ale finish at 1.020. No bottle bombs... not sweet... just a great full flavoured english ale. I've never made a stout, but just thought I'd tell you my experience with high FGs.

How did the previous beers taste?

 

[Damian44]

The yeast health should of been ok. I made a 1 liter starter from a fresh vial, than added that to a 2 liter starter and pitched 2/3 of it.
The mash temp was around 68-65C.

 

[Damian44]

I have had the same thing occasionally with my heavier beers. I do persist in trying to get the ferment active again, but if it doesn't move for three or so days I consider it done.

I had an English Brown Ale finish at 1.020. No bottle bombs... not sweet... just a great full flavoured english ale. I've never made a stout, but just thought I'd tell you my experience with high FGs.

How did the previous beers taste?

The stouts only been in the bottles a couple of weeks but tasts fine. Just tasting the bitter from the hydrometer and it tast frigin divine.

 

[np1962]

The yeast health should of been ok. I made a 1 liter starter from a fresh vial, than added that to a 2 liter starter and pitched 2/3 of it.
The mash temp was around 68-65C.

That's a fair range of temps, at 68 you will get a less fermentable wort than at 65. Expected FG would be calculated using a specific temp and 3 degrees would make some difference.

Nige

 

[Goofinder]

I'm guessing it started at 68C and fell to 65C over the course of the mash? If so, that's probably what did it as most of the conversion happens at the start so it would have been reasonably unfermentable.

Mash a bit lower next time if you want it to attenuate a bit more... say 66C or 67C. Also, your thermometer might be out of whack, but that doesn't really matter once you figure out what temp = what fermentability on your system.

 

[Damian44]

Thanks guys. Ill keep next mash right on 66C. Im pretty sure the thermometer is ok.

 

[afromaiko]

I had an English Brown Ale finish at 1.020. No bottle bombs... not sweet... just a great full flavoured english ale. I've never made a stout, but just thought I'd tell you my experience with high FGs.

Same here, and mashed pretty close to 70. Tried to get the FG down a bit by raising temp, adding a little bit more yeast etc but it really didn't want to drop much below 1.019. Kegged and drinking it tonight and it's lovely.

 

[Thirsty Boy]

One thing to remember is that the fermentable sugars are mostly sweet, and the dextrins are mostly not sweet.. so a bit of a guide to whats going on can be the "sweetness" of the final beer.

High FG and the beer is too sweet... then the beer is underattenutated vs its potential. Look at yeast health, pitching rate and yeast strain

High FG but the beer is not sweet - then you may have fermented what is there to ferment, but significant amounts of the sugars contributing to the PG are unfermentable sugars that the yeast couldn't deal with no matter how healthy they are.

It obviously more complicated than that, but it can be a good first cut place to look......

Lots of crystal in the recipe messes up the theory though... caramelised sugars are both sweet & unfermentable

TB

 

[white.grant]

The yeast health should of been ok. I made a 1 liter starter from a fresh vial, than added that to a 2 liter starter and pitched 2/3 of it.
The mash temp was around 68-65C.

Hi Damian,

For this style of beer I would have thought that mashing at those temps was appropriate - I do my milds and bitters at 67-68 and have no issues getting to the expected FGs. the apparent attenuation of 50% is well short of the published range for WLP002 so I think the problem may lie more with your fermentation. What temps do you maintain for the ferment?

cheers

grant

 

[buttersd70]

Also, your thermometer might be out of whack

This is my first thought. If your yeast health is any good at all, an apparent attenuation of 50% is, well, ridiculous. As Grantw said, 67-68 (or even higher) should attenuate a 1040 wort to around the 1010-1012 mark, depending on yeast strain adn specific wort composition. Even mashing at 70C, or even 72C, will still give higher attenuation than what you are getting.

Im pretty sure the thermometer is ok.

How sure are you? Really, really sure? Next mash, why not take a couple of litres for a fast ferment test. That'll answer a lot of your doubts.

 

[mje1980]

Hey guys. My last couple of batches have come up short of their FG. A Stout was supposed to drop to 1.012 but only made it to 1.017. I bottled it and no bottle bombs.

My current batch....

5.00 kg Pale Malt, Maris Otter
0.50 kg Crystal (Joe White) (72.0 SRM)
0.10 kg Amber Malt (22.0 SRM) Grain 1.79 %
50.00 gm Goldings, East Kent [4.80 %] (67 min) Hops 19.2 IBU
20.00 gm Goldings, East Kent [4.80 %] (30 min) Hops 5.8 IBU
20.00 gm Goldings, East Kent [4.80 %] (1 min) Hops 0.3 IBU
1.74 items Whirlfloc Tablet (Boil 15.0 min)
1 Pkgs English Ale (White Labs #WLP002) Yeast-Ale
25L

This one droped down from 1.040 to 1.020 after 7 days, but has not fell any further after 4 more days. It should finish at 1.012. Ive been rocking the fermenter as the yeast likes to drop out. What gives?

500g crystal is a lot, and will add to a higher fg, but not 1.020. I usually mash high, around 68, and get down to 1.008 with the right yeast,so i dont think that would explain the high fg ( by itself ).

 

[Screwtop]

What was the temp of your strike water Damien44?

High enzymic malts will begin to convert very quickly, conversion occuring as the water temp slowly drops to equalise at mash temp can be a bit of a problem when infusion mashing.

 

[clarkey7]

I had a similar issue with all recipes when I switched to AG - even lagers

Long story short - My thermometer was out by 3 degrees....when I thought I was mashing at 65 it was really 68 etc......

Don't always blindly trust equipment....test it with a known entity (a calibration solution for a pH meter, someone elses calibrated thermometer or do the boling water test for the 100 degrees for a starting point with your thermometer).

Good luck with it.

PB :chug:

 

[Ronin]

Thanks guys. Ill keep next mash right on 66C. Im pretty sure the thermometer is ok.

+1 on the thermometer. Even if you're pretty sure it's OK, it can't hurt to check it. I was using dial thermometers drilled through the side of my mash tun. I was getting very high F.G. for a few brews, calibrated it and it turned out to be 3C under at 65C. Once I dialed it up all my beers have been spot on.

How are you 'pretty sure'? What type of thermometer? If it's a dial one, they can be accurate at certain temperature, but quite out at others. I'd make sure it's calibrated at about 65C.

Good luck,

James

 

[Fourstar]

I'd Agree with the thermo possibility, its too easy to get wrong. if the threshold of the thermo is out by up to 5deg and you are tring to mash at 68, you could end up with a 73 deg mash (like i did for my 1st 2 AG's.)

Ended up switching from a sight thermometer which was getting confused by steam and or the pots surface to my new digital probe thermo which has a .1 +- deg threshold and have never had an issue with attenuation since. you can get them on ebay for $15 circa and are fairly reliable comparitive to the $100+ sight thermo i own.

As thirsty said, if its very dextrinous (big body but not sweet) most likely tyou have a thermo issue. if you are getting those expected FG figures from beersmith i have also found using a % of crystal up to 7-10% can cause for a diff of up to 2 SG points~ from what they calculate. I have never seen 8 points above the expected like you are having. I would say the 9% crystal you are using isn't the issue, just poor attenuation due to a highly dextrinous wort.

 

[Rob C]

Im also having an issue with not reaching my FG.

I Brewed 92.5 % JW Ale Malt and 7.5 % JW Munich. I mashed in at 65C

I racked this at 1.020 2 days ago and its still sitting at 1.020 The beer doesnt taste overly sweet. I brewed this with Wyeast 1469.
I have another started just about ready to be pitched into another brew would it be worth pitching some into this one to finish it off?

Cheers
Rob

 

[Damian44]

Thanks guys. Ive tested my thermometer against another thermometer at mash temps and they were within a half a degree of each other. Mind you the other thermometer would turn itself on and off.
So it was faulty to start with.

I Biab and i had the water at 68.5C when i added the grain. Temps only droped a half a degree.

I have a fridgemate so my worts been sitting pretty on 20C. I just took a hydrometer reading and took its temp with the thermometer, and it read 20C.

 

[Damian44]

I guess I'm in the market for a new thermometer. Could anyone recommend one under $100?