BIAB flat beer - using dextrose

[Anth M]

G'day brewers,

I've got a head-scratcher here.

I do all-grain BIAB and I've noticed ever since bulk priming with dextrose (using the calc on this site) all my brews are on the flat side. Some background on how I roll:

• I mostly do pale ales, wheat beers, stouts
• My recipes are scaled to 15 L each time
• I hit (or close to) my gravity readings
• I ferment and carbonate in temp controlled fridge for 14 days each
• I rack 14 L into a bottling bucket each time (1 L loss to crud etc)

When I bulk prime I use the BF calc and input these numbers:

• Units: Metric
• Amount being packaged: 14 L
• Volumes of CO2: I'd go 3 or 4 (but there's no diff in the carb level)
• Temp of beer: Whatever I fermented at.

I then weight out the corn sugar (dextrose) value it returns i.e. 180 gm, add it to a pot and cover with just enough water then boil for a minute or 2. I pour into bottling bucket then rack my 14 L wort and bottle from that point.

I recently ditched my air lock and use glad wrap, probably not the cause but worth noting.

I've had brews that were still flat 6 weeks after bottling.

Any advice appreciated!!

 

[thunderwagn]

Thinking keep your bottles out of the fridge. I would shoot for at least 70 degrees f to carbonate at (room temp) for a couple of weeks..

 

[Mase]

Sorry for the tangent, but what part if the process are you ditching the airlock in favor of glad wrap?

 

[Nosybear]

Temperature is something very important - the warmer the beer got, the less carbonation it retained from fermentation! That may be a cause....

 

[J A]

I ferment and carbonate in temp controlled fridge for 14 days each

There's your problem...Let the bottles sit at 70 degrees for 2 weeks like Thunderwagn says.

 

[Anth M]

Sorry for the tangent, but what part if the process are you ditching the airlock in favor of glad wrap?

Hi Mase,

I use glad wrap because with the airlock attached it won't fit in my fridge - it's pretty small. I don't chill my beers. When the boil is done I add about 3-4 litres of cold water which brings the wort down to 60-70 C then I glad wrap it and put in my fridge. It chills overnight then I pitch yeast when the wort is around 18-24 C depending on what recipe says.

 

[Anth M]

Thinking keep your bottles out of the fridge. I would shoot for at least 70 degrees f to carbonate at (room temp) for a couple of weeks..

Hi thunderwagn,

I should have stated in my earlier post but my fridge is temp controlled so I have a heat pad in there as well. I don't take gravity readings during fermentation, I just leave it for 2 weeks then bottle - maybe that's wrong and I should bottle as soon as I get 2 exact readings? I would then bottle and put back in the fridge for a further 2 weeks a few degrees higher than my ferm temp - usually around 20-24 C (68-76 F)

After the 2 week carbonation period I can see sediment at the bottom of the bottle - is that good? I don't think it's the dextrose. It seems more like the yeast isn't active during that carb period.

 

[Anth M]

There's your problem...Let the bottles sit at 70 degrees for 2 weeks like Thunderwagn says.

Thanks JA,

I replied to thunderwagn and explained myself a bit better ...I do carb at that temp for 2 weeks.

 

[ChicoBrewer]

Do you have a good capper? Maybe the bottles aren't sealed properly. Might sound silly but if you put a balloon over the cap and it inflates...

 

[GFHomebrew]

Yep sediment is just that. Is there sediment in bottom of these non carbed beer. It seems odd to me only other explanation is no yeast but thats bear impossible.

 

[Anth M]

Do you have a good capper? Maybe the bottles aren't sealed properly. Might sound silly but if you put a balloon over the cap and it inflates...

Howdy,

That is seriously the only thing that makes sense. I'll be bottling in 2 weeks so will give a few balloons a go. cheers.

 

[Anth M]

Yep sediment is just that. Is there sediment in bottom of these non carbed beer. It seems odd to me only other explanation is no yeast but thats bear impossible.

Yep there is sediment at the bottom of each carbed bottle. Is that a good sign?

 

[Nosybear]

Yep there is sediment at the bottom of each carbed bottle. Is that a good sign?

It just means something settled out of the beer, likely some yeast and some trub. I'm still betting your calculation temperature was lower than the actual temperature your beer reached, so that the CO2 the calculator was expecting wasn't there. Carbonation is the sum of the CO2 dissolved in your beer and the CO2 created by the yeast from the priming sugar. If your initial CO2 was low, caused by heat driving CO2 out of solution, your carbonation would be low.

 

[Hogarthe]

If you are aiming for 3 or 4 vols but getting flat beer I'd be suspicious of your capper. Even if you had no co2 left over from the original fermentation adding enough sugar to get to 4 vols should leave you with enough carbonation to not be flat. Even if you only got 2 vols it wouldn't be flat. I think you are leaking gas out of the bottles.

 

[Anth M]

Thanks all for the help. There's been a development in the mystery.....

I should have twigged earlier but looking back on my past brews all the ones that have been flat I used Wyeast smack packs:

• Wyeast 3056 Bavarian wheat
• Wyeast 3944 Belgian witbier
• Wyeast 1728 Scottish ale
• Wyeast 2124 Bohemian Lager

All the other brews that were fine I used US05.

So that rules out sugar type/amount, leaky bottles etc. I ferment for 2 weeks for every brew and I only take a gravity reading when I bottle (not for comparison prior to bottling), perhaps I'm leaving it too long for Wyeast and it's settled out by the time I bottle? Thoughts?

 

[ChicoBrewer]

Spooky. I use Wyeast all the time. No problems when I bottle (which admittedly isn't often)

 

[Nosybear]

Thanks all for the help. There's been a development in the mystery.....

I should have twigged earlier but looking back on my past brews all the ones that have been flat I used Wyeast smack packs:

• Wyeast 3056 Bavarian wheat
• Wyeast 3944 Belgian witbier
• Wyeast 1728 Scottish ale
• Wyeast 2124 Bohemian Lager

All the other brews that were fine I used US05.

So that rules out sugar type/amount, leaky bottles etc. I ferment for 2 weeks for every brew and I only take a gravity reading when I bottle (not for comparison prior to bottling), perhaps I'm leaving it too long for Wyeast and it's settled out by the time I bottle? Thoughts?

Not a factor. I use those all the time. Yeast is not your issue - there are enough cells in the beer to bottle condition even after months of lagering. You either miscalculated the priming sugar, misweighed it, got your beer hot enough to kill the yeast or your caps are leaky but leaky bottles would be completely flat, not partially carbonated. Possibly you lost the gas from the beer through getting it too warm or agitating it, that could result in partial carbonation. But yeast is not your issue.

 

[The Brew Mentor]

I'm betting on the caps or the capper.

 

[Nosybear]

I'm betting on the caps or the capper.

If they're completely flat, I agree.

 

[Yooper]

How much priming sugar did you use for the flat batch, the amount of beer you primed, and what is the temperature you are holding the bottles at? (I read through all of this, but didn't see the exact amount and temperature, so please excuse me if it's a repeat. I just want to make sure I have the facts).