Fermentation Time

[SG9090]

I know there is no straight forward answer for this however i was wondering in general how long dose everone give the primary fermentation.

So far have only brewed ales.

Why i ask is i have been leaving my primary for 10 days at the correct temp for the recipe and always get down to 1.002 to 1.006 even though a recipe might say it will finish down to 1.015. Should i be stopping the beer once i hit the final gravity of a said recipe or continue on the way i have been going. Im thinking the way i have been going will change the taste of the final beer to maybe something not quite right.

Cheers, Shane

 

[eXpeLL]

I'm by no means an expert (much closer to noob) but I'd say ferment until you're SG is stable over 24-48 hours. Otherwise if you're bottling and fermentation hasn't finished you'll end up with grenades. In terms of time (and a general rule) I think true lager yeasts will take longer to ferment at optimum temperature (lower temps) than ale yeasts (higher temps). I only primary ferment and usually bottle/keg no earlier than 2 weeks (although I predominantly do ales but still stay true to the stable SG rule). Feel free to correct me anyone.

 

[speedie]

For ales I would put your 1006 in the too low area

If your yeast has an attenuation of say 70 % then you can predict with some confidence the terminal gravity of your batch will drop by three quarters approx

Ie 1.055 -1 = 55 x .3 = 16.5 plus 1 = 1.016

Terminal gravity

speedie

 

[bignath]

I'm by no means an expert (much closer to noob) but I'd say ferment until you're SG is stable over 24-48 hours. Otherwise if you're bottling and fermentation hasn't finished you'll end up with grenades. In terms of time (and a general rule) I think true lager yeasts will take longer to ferment at optimum temperature (lower temps) than ale yeasts (higher temps). I only primary ferment and usually bottle/keg no earlier than 2 weeks (although I predominantly do ales but still stay true to the stable SG rule). Feel free to correct me anyone.

Good post mate.

The only thing i'd change is the duration of time that has stable gravity readings. I'd typically go for 2-3 days of the same reading as opposed to 1-2 (48hours), but other than that it's very good advice.

Shane, she'll be done when she's done mate. If you're getting lower gravity readings than expected i wouldn't worry about it too much. Have you checked your hydrometer for accuracy?

cheers,

Nath

 

[browndog]

1.002 to 1.006 is very low for an ale or a lager for that matter. However, it the beer is tasting good, why change? if you said my beers are turning out dry and bitter, then you would need to do something about it. You have not said how you brew or what type of beer you are brewing so it is very hard to comment. Give us a bit more info. If the recipe calls for an FG of 1.012-14 and you end up with 02-06 the beer will taste nothing like it is supposed to.

cheers

Browndog

 

[bignath]

For ales I would put your 1006 in the too low area

If your yeast has an attenuation of say 70 % then you can predict with some confidence the terminal gravity of your batch will drop by three quarters approx

Ie 1.055 -1 = 55 x .3 = 16.5 plus 1 = 1.016

Terminal gravity

speedie

In stark contrast, this is a good example of a shit post.

how the hell did you pull those numbers?

Oh wait i got it, the formula goes a little like this.

"randomly select figure to substitute the OP's original gravity, subtract another random number and multiply this by unrelated figure. then put the same number back in the equation, and holy **** batman - a random gravity number that MAY also be considered too high for fermentation to finish"

1006 is not TOO unrealistic for a good healthy fermentation at all. I've done it regularly.

Shane, don't listen to the advice that is quoted as above. Check your hydro for calibration buddy, and then take it from there to troubleshoot.

Cheers mate,

Nath

EDIT: "you can predict with CONFIDENCE that you'll APPROX. get a drop by....." love it!

 

[MHB]

Shane you do need to provide a bit more information (like the OG) and whether it is a Mash or Extract brew we are talking about, what other ingredients you used (like dry enzyme or the mash temperature), if you want a more complete answer.
Although clearly what youre experiencing is a little out of the norm, its far from impossible and I have seen beers finish well under 1.000, when dry enzyme/cool mashing is involved, if you have taken good readings do the calculation below. Everything being equal you wouldnt expect apparent attenuation to be over 80% more likely in the 75-78% range, and yes you need to check youre equipment like hydrometers and thermometers and the temperature you are taking your readings at.

speedie again sorry to say you havent grasped the concept again, apparent attenuation is calculated thusly.
(OG-FG)/OG * 100 = Apparent attenuation%
For the numbers you used (55-6)/55 * 100 = 89.1% not 70%
MHB

 

[matr]

In speedies defence :unsure: h34r: he was showing how to calculate expected terminal gravity not apparent attenuation.

I actually found it informative..

 

[MHB]

speedie
Oh you are right that if the beer started at 1.055 and finished at 0.016 the apparent attenuation would be ~70%, that is not however the question being asked. And you are right in saying that from 1.055, 1.006 is normally too low. However without the OG were just guessing based on using your method the OG would have to have been closer to 1.020. If you want to manipulate the numbers (and that can be very useful) you need to use the full equation rather than a shortcut method well at least until you are comfortable with how the works.
MHB

matr
Yes I realised that after I posted and was writing a clarification, precisely because calculating terminal gravity is all about apparent attenuation
M

 

[TSMill]

Both calcs are exactly the same (expressed differently), and will calculate the same FG, given the same OG and apparent attenuation.

Obviously the first calc was provided as an example only with arbitrary OG and %attenuation numbers, a lower FG (say 1.0048) and higher attenduation (85%) would get you into the ballpark of 1.006.


:beer:

 

[SG9090]

One thing i have always thought that my beers are always a little too bitter. I was thinking i should knock off a few IBUs in the future, when i read the gravity of this Premium Bitter a quick taste and again a little to bitter, looked the the recipe which says it should finish at 1.012 so i thought if i had stopped it then maybe it would be a fraction sweeter which would knock that bite from my preception of it been a little bit bitter.

Will yeasts ferment much lower than the given specs given 10 days in the correct temp for the yeast?

I am using a 3V herms system, AG.

I have checked the hydro and it reads tap water at 1.000 though i did not note the temp, will check again later tonight.

If there is any more info you may need please ask.



Below is my latest starting at 1.050and finished at 1.004

Batch Size (L): 28.00 Wort Size (L): 28.00
Total Grain (Kg): 6.02
Anticipated OG: 1.050 Plato: 12.36
Anticipated EBC: 23.5
Anticipated IBU: 29.6
Brewhouse Efficiency: 74 %
Wort Boil Time: 60 Minutes

Actual OG: 1.047 Plato: 11.72
Actual FG: 1.012 Plato: 3.07

Maashed at 66deg

Grain/Extract/Sugar

% Amount Name Origin Potential EBC
-----------------------------------------------------------------------------
88.4 5.32 kg. Maris Otter Thomas F Great Britain 1.038 7
4.7 0.28 kg. Aromatic Malt 40_EBC Belgium 1.036 40
4.7 0.28 kg. Crystal 120L Great Britain 1.033 236
2.3 0.14 kg. Biscuit Malt Dingermans Belgium 1.035 57

Hops

Amount Name Form Alpha IBU Boil Time
-----------------------------------------------------------------------------
35.94 g. Goldings - E.K. Pellet 5.80 24.5 60 min.
15.00 g. Goldings - E.K. Pellet 5.80 3.4 20 min.
15.00 g. Goldings - E.K. Pellet 5.80 1.7 1 min.


Yeast
-----

WYeast 1968 London Extra Special Bitter
Fermentation at 20deg for 10 days



Honestly!!! thank you all for your help.
Shane

 

[MHB]

Shane there are two really obvious things to look at first

1968 will show apparent attenuation of 67-71%, you are getting 92%, that simply shouldn't be happening.
Was it a fresh yeast or a re-culture? Because 91% is well outside the bounds you would expect for that yeast and you would have to ask if there was something else in there to.

You need to check your mash thermometer, I suspect it's about reading high by 3-4^oC, If you thought you were mashing at 66^oC and you are really at 62-64^oC you are creating very fermentable wort.

The reduced body from over attenuation and relatively fewer higher sugars will make the beer taste bitterer. I wouldn't muck around with the hopping too much, sort out the attenuation issue and the bitterness will look after itself.

MHB

 

[manticle]

I know there is no straight forward answer for this however i was wondering in general how long dose everone give the primary fermentation.

So far have only brewed ales.

Why i ask is i have been leaving my primary for 10 days at the correct temp for the recipe and always get down to 1.002 to 1.006 even though a recipe might say it will finish down to 1.015. Should i be stopping the beer once i hit the final gravity of a said recipe or continue on the way i have been going. Im thinking the way i have been going will change the taste of the final beer to maybe something not quite right.

Cheers, Shane

Time is not really the issue. If bottling there's no way you should be stopping gravity early and I would argue that even though your kegs probably won't blow up, that there are other issues with not letting beer ferment right out. Yeast needs time to clean up its byproducts once it's done eating sugar.

In my experience, different yeasts take different amounts of time. Compare my last coopers bottle yeast brew (FG in 5-6 days) to most UK yeasts I've used (2 weeks and up with some rousing in between).

 

[mckenry]

One thing i have always thought that my beers are always a little too bitter.
Shane

Shane,
Another thing to consider is infection. Some wild yeasts will ferment your beer out more than the yeast you use. If you think your beers are too bitter and the gravity is way below expected, this is a possibility. Not all infections make beer undrinkable. Some are simply a 'bitter taste'.
mckenry

 

[Strange Brew]

(2 weeks and up with some rousing in between)

Haha, you're not wrong there. Lazy little UK flockers need a boot up them every now and then.

 

[SG9090]

Problem solved,
I had a very fine hairline crack in my hydrometer, When i would read water i put the hydrometer in the tube and instant correct reading, when i read beer there is always bebbles in the tube at the top making it hard to take a reading so i would always leave it and check it an hour later, in that time a small amound made it into the hydrometer weighing it down.
It was so small hard to see crack but a mm or two get in and i never noticed it.

Thanks everyone for you help.

Shane