Beer Not Fermenting All The Way - Final Gravity 1025 - 1030?

[philski]

Hi All,

I'm having a serious problem with my fermentation....

The last 4 brews I've done are only 2.5-3% alcohol! Not good when I have been aiming for 4.5-5%!!!

The problem is the same for the last 4 brews... The beer is not fermenting out all the way. It gets down to a final gravity of 1025-1030 or thereabouts, from 1045-1050 and stops... I even kept one in the fermenter for over 2 weeks and it didn't get any lower than 1030.

Now I'm relatively new to all grain brewing, but I'm working out everything using Beersmith. So for a 23L batch, I have 5.3kg of Joe White pale/vienna malt and about 200-250g of crystal. Beersmith says the original OG est is 1050 for 66% efficiency and an estimate of 1013 final. For the last brew I got an OG of 1047 and final of 1024.

I'm uising Safale US05 yeast, fresh from Grain and Grape. I've tried a starter, rehydrating the yeast and dry pitching and it doesn't seem to make a difference. All the beers bubble happily for a few days, but they don't get down to the expected low gravity. They are fermenting at about 20-22 deg.

I thought maybe the beersmith data I had was wrong but if it's starting at a gravity of around 1050 I assumed it would ferment out. Obviously this isn't the case.

Could it be that my mash technique is not yielding enough fermentable sugars? Would the gravity be 1050 if this was the case?

I'm stuck here. Any help would be much appreciated as brewing is now becoming frustrating and not relaxing, not where I want it to be....

More info:
- Analysing everything with Beersmith
- Mashing using a modified esky at 66 degrees (single infusion)
- I've tried several different recipes

Does anyone know what could be causing this problem? In all the extract and partial mash brews I've done (and there have been a few) never had this issue once! Could it be my mash technique?

Thanks

 

[manticle]

How confident are you in your mash temps and what have they been measured at?

Are you measuring with a refractometer or hydrometer? If it's the refrac, you wouldn't be the first to get a high measurement due to not converting after the presence of alcohol.

If a hydrometer, how confident are you that it is reading correctly?

Ditto for your thermometer.

 

[philski]

How confident are you in your mash temps and what have they been measured at?

Are you measuring with a refractometer or hydrometer? If it's the refrac, you wouldn't be the first to get a high measurement due to not converting after the presence of alcohol.

If a hydrometer, how confident are you that it is reading correctly?

Ditto for your thermometer.

I've measured the mash temp with 2 small digital thermometers... not the most expensive in the world but they seem accurate enough (eg ambient temp and temp of water seem about right). I have been meaning to get a decent one but haven't got the cash at the moment. Not exactly sure what type/style is best (or most accurate) anyway.

I've been measuring with a refractometer that has the gravity readings on it (see here http://discount-instruments.com/link/refra...brix_scale.jpg) - do I still need to convert with this? I also compared one brew with the hydrometer (which i've used for other brews), and the results were comparable (not exactly the same but only out by a few points).

I've even tested it by having a few beers and I certainly can't feel the effects when compared with a normal brew.

 

[BreathingHeat]

What temp are you mashing at?

 

[Wolfy]

How (well) are you aerating the wort before pitching the yeast?

 

[philski]

I'm mashing at 66 degrees.

I've aerated the wort really well, by pouring it into the side of the fermenter via the tap of the kettle while the kettle is at height, then stirring vigorously.... I thought this was the problem after the first one, but I was proven wrong.

 

[sean_0]

I've even tested it by having a few beers and I certainly can't feel the effects when compared with a normal brew.

What about taste? At 1.025-1.030 it's gonna taste very sweet, if it were me I would have trouble drinking more than a pot or so of beer that sweet in one sitting.

 

[ekul]

I've been measuring with a refractometer

This here is probably your problem. It either this or you're fermenting too low. Sometimes my fermenting fridge will dip below 14C at night in winter, making my brew take a little longer. If i were you i'd start fermenting at 19C and see if that works. US05 is a hardy yeast and i've never had it fail on an all grain batch.

 

[np1962]

I've been measuring with a refractometer that has the gravity readings on it (see here http://discount-instruments.com/link/refra...brix_scale.jpg) - do I still need to convert with this? I also compared one brew with the hydrometer (which i've used for other brews), and the results were comparable (not exactly the same but only out by a few points).

It makes no difference whether your refractometer reads in plato, brix, SG or bunny rabbits, YOU NEED TO ADJUST FOR ALCOHOL ONCE FERMENTATION STARTS!

This is getting as common as 'My airlocks not bubbling' questions.

Cheers
Nige

 

[manticle]

I've been measuring with a refractometer that has the gravity readings on it (see here http://discount-instruments.com/link/refra...brix_scale.jpg) - do I still need to convert with this? I also compared one brew with the hydrometer (which i've used for other brews), and the results were comparable (not exactly the same but only out by a few points).

I've even tested it by having a few beers and I certainly can't feel the effects when compared with a normal brew.

This is almost undoubtedly your problem and a fairly common one.

The presence of alcohol skews refractometer readings making them appear higher than they actually are.

There's a chart here: http://www.aussiehomebrewer.com/forum/inde...showtopic=47454 (use the bottom one) or you could try the calculator here:

http://brew.stderr.net/refractometer.html which might be easier to follow.

You'll probably find your beers are attenuating fine.

Do the instructions on refractometers not include this information?

 

[milob40]

i suffered the same problem after upgrading my burner, i measured my temp and got 69 as strike temp for a 66 mash temp.
and have now fertilized the garden with sweet beer. check your strike temp and then check it again.
the heat in the keg lip was taking it's time transfering into the brew (the bottom lip was sizzling hot after killing the flame).
it was hitting 72-73.
give it a few minutes at rest before measuring strike temp. fixed my problem, not sure if it'll fix yours.
if your sg seems ok, then their is a good chance your mash temp was too high as mine was so i made dextrinous sugars that are less fermentable instead of fermentable sugars. (advice from beer gods) .
shake the living #@%^t out of your wort before pitching to ensure enough oxygen too.
this was my learning curve . i was using us05 myself. i have moved to nottingham for a wee bit till i get my swill levels back up. :icon_cheers:
just wondering if it could be a bad batch of yeast as there has been a few posts about this of late.
not wanting to start rumours or anything sinister like that .
i'm no expert but just simply sharing my experience. :icon_cheers:

 

[bignath]

It makes no difference whether your refractometer reads in plato, brix, SG or bunny rabbits, YOU NEED TO ADJUST FOR ALCOHOL ONCE FERMENTATION STARTS!

This is getting as common as 'My airlocks not bubbling' questions.

Cheers
Nige

There should be a sticky or something about using a refractometer.

Actually one about creating a decent mash tun manifold wouldn't be bad either :blink:

 

[manticle]

There should be a sticky or something about using a refractometer.

Actually one about creating a decent mash tun manifold wouldn't be bad either :blink:

http://www.homebrewdownunder.com/index.php?topic=948.0

 

[np1962]

http://www.homebrewdownunder.com/index.php?topic=948.0

My manifold doesn't bounce around like that. :blink:

 

[philski]

Thanks all. I will get another hydrometer and measure it with that, then I will compare with the adjusted refractometer readings when i get home tonight. The refracto instructions didn't mention any of this!

Ok, so checking out the chart in the thread it looks like if my OG was 1046 (mine was 1047) and the FG on the refractometer reads 1024 (which it does), the adjusted reading is actually 1010. This sounds reasonable so hopefully I can prove it tonight comparing with a hydrometer!

The beer didn't taste sweet, in fact it tastes really good!! But I still this it's low alcohol, as I said, you can drink a few and not feel the effects.

Also, the fermentation temp stays at about 20 degrees as I have it in a cupboard under the stairs in the middle of the house, the temp is pretty much a constant 19-20deg in there even in winter. I've also been checking the temp and it does stay at 20.

I will post my results of measurements tonight...

 

[manticle]

My manifold doesn't bounce around like that. :blink:

Then it's made from the wrong material.

My manifold is pert.

 

[philski]

Measured the gravity with a hydro last night. 1014. Yes!!!! Slightly off what i read off the adjusted refractometer chart, but once it is finished in the secondary I will check it all again and post the refracto vs. hydrometer and adjusted readings!!!!

I'm still not sure why the last batch didn't ferment, must have just been a dodgy one... I did check the refracto vs hydrometer on the last batch and I was getting about the same gravity. It was 1030 on the refracto and about 1026 or so on the hydro. Water under the bridge now that this batch worked out though. looking forward to tasting it in all its glory!

Well I think I've finally found the solution, thanks for all your help! I'm now dreaming up what concoction to do next rather than debating about whether to even do another brew.

Thanks again. More data to follow in a few days...

 

[bignath]

I'm still not sure why the last batch didn't ferment, must have just been a dodgy one...

G'day philski, glad to hear you're getting the problem sorted. It's one of the most common forum threads, gravity issues and refractometer's not being adjusted for the presence of alcohol etc...

Just wondering though, how do you know the last batch didn't ferment?

If your tools weren't being used optimally there's every chance it did finish properly. Particularly if it tasted "like beer".

I don't know anyone that could stomach drinking beer that only moved a few points, or even halfway through expected gravity range will still produce sickly sweet cordial. I don't reckon i could do a stubbie of it...

Anyway, glad to hear your sorted, and keep us posted of results mate.

Nath

 

[philski]

Just wondering though, how do you know the last batch didn't ferment?

If your tools weren't being used optimally there's every chance it did finish properly. Particularly if it tasted "like beer".

This is the exact reason I have been confused!!! The only reason I still think the last one didn't ferment is because I measured it with the hydrometer and it was 1026 or thereabouts. I'm normally pretty good with keeping records but at the time I was angry with the beer fermentation gods I didn't write down the exact figure. The beer does taste good and isn't overly sweet as you would expect. I'm thinking now I may have just stuffed up the measurement, and perhaps it is just on the lighter side and is a 3-4% beer, which is in fact quite drinkable.

Anyway, this latest batch is fine thanks to the advice I've received. which is excellent news!

So what is the most accurate way of measuring gravity? Hydrometer or refractometer? I originally got the refractometer as it seemed like the more accurate option. However it seems there is some room for error when adjusting for alcohol for the refractometer. Thoughts?

 

[cdbrown]

I use the refrac during brewing to see what first runnings are, pre-boil and then post boil to see how much water i need to add (can't do full boil). Then once cool and ready to pitch I use hydro, samples during ferment and at end all hydro. Can't be bothered with conversion tables.