puzzling final gravities

[akardam]

it seems that my 3 last batches have a lower attenuation than those suggested in the respective recipes by 5-10 points and this puzzles me.

so i brewed the following:
1. irish red (og:1.052,fg:1.016) and should have been 1.011.
2. a nut brown ale (og:1.055, fg:1.024!!) and should have gone to 1.014.
3. a belgian honey pale ale (og: 1.056,fg: 1.021) and should go to 1.015.

the temperature is constant on the upper end of the ale fermentation scale at 22C (about 72-73F). and I have left each one for 10 days in primary and a week in the secondary.

mashing occured at 154F and used dried yeast nottingham or safale us04 for pitching.

i tried stirring up the yeast on the bottom and pitching some wort from my honey ale at high krausen to the brown ale, but nothing..

any suggestions.. i'm a bit frustrated .. thanks guys!

 

[Tinga]

the first and third are not too far off the second one is a little suspect though.

 

[akardam]

just to add to this. i aerated well the wort with a proper aerator and add some yeast vits.

 

[akardam]

well, your are probably right.. but why is this systematic? what am i screwing up?

 

[Tinga]

ok just re read this. leave in primary longer. three weeks normally. this might get you those extra couple points you are looking for.

 

[Brew-boy]

Leave it in primary no need for a secondary. Let the yeast do there job and go 14 days min. then check the gravity, wait 3 days and check it again.

 

[akardam]

i already got 2 out of 3 in secondary already.. in future, i'll be scraping the secondary stage i reckon. but now? what do i do for the 2..mmm

 

[Yooper]

Are you 100% sure your thermometer is correct? Mashing at 154 and using nottingham should cause full attenuation.

Try mashing at 152, and see if that improves your attenuation.

 

[yodalegomaster]

I would be rousting the fermentor every other day for a 3-4 weeks, It will get bone dry then. The last part of the fermentaion is finished by either rousing (shaking), time or both.

 

[steveo929]

I agree with Yooper; calibrate your thermometer (look it up on youtube if you're unsure). Also, you might want to look into the yeast...how about getting into some simple starters and going into liquid yeast? Are you aerating your wort by shaking, air stone, or not at all? Also, another biggy may be the fermentation temps. That temperature is a little high and your yeasties may go all crazy to begin with then poop out quickly without finishing up. I'm not a big fan of rousing yeast unless it's absolutely necessary. Good luck!

 

[ajf]

I also agree with Yooper. If the thermometer is reading low, you could be mashing at an excessively high temperature.
Also, how much water are you using to mash with? If you do a thick mash (say 1 qt per lb grain, or 2.1 liters per Kg) that can also contribute to low attenuation (according to Greg Noonan's New Brewing Lager Beers).
The other thing is (as Brew-boy said) that you are transferring to a secondary after 10 days. Most of my beers are still fermenting (albeit slowly) at that point, and transferring to a secondary will get rid of a lot of the yeast before they have finished, slowing down the fermentation process even further.
I usually keg after 3 - 4 weeks in the primary, and check the FG at that time. If the FG is where it should be (based on previous brews), I go ahead and keg. If the gravity is still high, I give the beer a rousing, and try again after another week or two.
Only once in 35+ years has this failed to work. I roused that brew a second time, and it was ready two weeks later.

-a.

 

[magnj]

Notty is going to be real fruit above 70f. But I agree with the other guys, rouse the yeast and give it some more time. You may also look into a Wyeast pack and starter to really kick things off.

 

[akardam]

ok thanks for your replies!
1. i have to check thermometre during next brew. However, this idea urged me to check my hydrometre. and i was shocked to find out that it read 1.004 with tap water !!!!!!!!
DO you believe it??? that obviously means, given the linearity during constant temperatures, that the actual OG was -4 points. I assume alcohol content is same. Right?

2. I mashed with 1.25-1.35 water/grain ratio. i didn't know it played a role in fermentable/unfermentable sugar production. i thought it was a function of only mash temperature. i'll keep this in mind and check out your suggested reference.

so take home message is:
a. keep in primary until fermentation actually stops before racking or whatever, because then we can roust the yeast up a bit and bring it a few points down.secondary conditioning is a tad overrated. correct?
b. check thermometre make sure indication is actually true.
c. check yeast characteristics, eg attenuation, fermentation temperatures, etc.

last question; i have this pilsner enzyme, i reckon its an amylase enzyme (doesnt explicitly say on sachet) and i pitched a bit into my small separate forced fermentation sample just to see if yeast will respond. Do you think that this would be wise to pitch in (in small amounts) to fermentation vessel?

cheers to everybody!