overcarbonation or need to chill more

[PaulP]

Just a quick question,i have some coopers bav lager thats 3mths old
and it is really overcarbonated.Is it to much bulk priming with dextrose
(180gr)or does it need chilling for a couple of days.I have only tryed it
straight to the freezer for a30mins then drink.

[lethaldog]

There is alot of factors involved like, what temp its brewed at, what type of yeast was used etc

180gms is fairly standard under the right conditions

[Chris]

It could be that you bottled just a fraction too early as well. It could be that you have a mild infection.

Is it gushing, or just uber-fizzy? (Where is the brewer formerly known as Ilike'emfizzy when you need him?)

180g of dextrose will usually give you beach-ball sized bubbles, and lots of them. Try using 150g next time for a comparison.

[gregb]

... (Where is the brewer formerly known as Ilike'emfizzy when you need him?)...

Now known as 'The Carbonator' but hasn't been heard from for about six weeks.

Cheers,
Greg

[DJ]

... (Where is the brewer formerly known as Ilike'emfizzy when you need him?)...

Now known as 'The Carbonator' but hasn't been heard from for about six weeks.

Cheers,
Greg

Isnt he know Cortez the Killer?

[Cortez The Killer]

Nah

Cortez was formerly "da_damage_done"

He truly was a hero of time!

[Chris]

Oh, so THAT'S where damage went.

[cleverpig]

Ive had the same problem with a coopers bav lager. Used a saflager yeast, and bulk primed with 180g sugar. It's about 4months old now. It pours with a 10 finger head, just a bit too much for my liking. I'm guessing at the following possibilities:

• Temperature dropped from 14C to below 10C (not sure how low, as strip thermometer only goes to 10C ) over 2 weeks, fermentation may not have completed.
  Final volume after bulk priming was about 21litres for this volume 160g may have been about right for priming.

I got hold of some One-Wire temperature sensors, which I'm planning to use for monitoring the temperature under the house, it seems to stay pretty cool under there, and hopefully it's like it all year round. If I put the fermenter in a small enclosure, I figure hooking up a light bulb to a relay controlled by the One-Wire bus, may be enough to keep the temperature at a constant rate. Should be a good setup once working, and all controlled from the study up stairs

[rwh]

When you ferment at lower temperatures, the solubility of CO2 in your beer is increased. This means that there is more CO2 dissolved in your beer before you prime, so you need to adjust the quantity of priming sugar downward.

http://oz.craftbrewer.org/Library/Metho ... uide.shtml

[cleverpig]

Thanks rhw, great link

Had a quick look, and it appears for that temperature 180g is about double the required amount for that style of beer, Need to read it more throughly and do that sums.

[bhami]

Over carbonation could be a problem with your yeast. If your yeast is not healthy you may get a slack fermentation that takes a long time to ferment out. Next time make a yeast starter if possible, or if you cant be bothered and you are using a dried yeast sachet hydrate it in warm water (30 degrees C) for 15mins before pitching it.

Over carbonation and exploding bottles may also be caused by infections that consume the unfermentable sugars (dextrins) that the yeast could not. Sterilize, Sterilize, Sterilize.

If you do have an over carbonated beer chilling it to cold temperatures before opening it will help, but drinking beers at very cold temperatures means you will loose some of the flavours. You could let it warm back up in your glass.

Cheers

Ben H

[cleverpig]

Ok I've read the link and done the sums,

For a European Lager style (Coopers Bavarian with saflager) the expected range of CO2 is 4.3-5.3g/L, so if I go for 4.7g/L then,

for fermentation temperature of 10C the level of CO2 in the beer is 2.36g/L
therefore 4.7-2.36 = 2.34g/L required from bulk priming

Multiply that by 2.16g for sugar (amount required to add 1g of CO2 to 1 litre) = 5.0544g/L of sugar required
Therefore for 21L that's 106g of sugar required for bulk priming.
Which is a lot less than the 180g I added.

The site goes on to mention variable temperature history can affect the amount of CO2 that is absorbed, which means variable temperature during fermentation is going to effect the final carbonation rate. Which I guess why is every brew is different......

[bhami]

One thing I forgot to mention, there is a simple way you can check to see if your fermentation is complete. A couple of days before bottling check the gravity with a hydrometer and then check it again on bottling day. If the reading is the same you can be pretty sure fermentation is complete, if it has dropped fermentation may not be complete so put off bottling for a couple of days repeating the process.

Cheers

Ben H

[BierMeister]

The site goes on to mention variable temperature history can affect the amount of CO2 that is absorbed, which means variable temperature during fermentation is going to effect the final carbonation rate. Which I guess why is every brew is different......

Hit the nail on the head there mate. Generally though if you go by the max temp the brew was at and conteract for super saturation then you should be fine.

[cleverpig]

Hit the nail on the head there mate. Generally though if you go by the max temp the brew was at and conteract for super saturation then you should be fine.

I guess it's why it's number 4 on Chris's "Simple things that make HB better" topic http://www.homebrewandbeer.com/forum/vi ... php?t=1966