Low carbonation problem

[bobtheUKbrewer2]

I brew 3.8% pale SMASH beers. I bottle 6 or 7 days after yeast pitch. I prime bottles with brewing sugar - one heaped teaspoon per litre. Bottles are placed in a room that is 17 to 22 deg C. After 3 to 4 weeks I start to try them, they taste fine but lack adequate carbonation. BIAB 25 litre batches, SO4 yeast. Mash at 67 - 68 deg C. Jug and glass are rinsed with tap water to ensure no soap film. Thanks.

 

[mac_1103]

I don't know what "brewing sugar" means, but anyway you should use a priming calculator and weigh whatever sugar you use.

 

[bobtheUKbrewer2]

I think it is dextrose, very common in UK

 

[mac_1103]

We call that corn sugar or priming sugar on this side of the pond. Not sure of the conversion from "heaped teaspoons" to grams, but my first guess would be that you're not using enough sugar to get the level of carbonation you'd like.

 

[bobtheUKbrewer2]

Mac - a heaped teaspoon of corn sugar is 7 grams. Percieved wisdom over here is less than that per litre. Especially bottling in 6 days - you expect bottle bombs (often) when I post my techniques...this is a recent phenomenon, in past years I used PET bottles to monitor pressure, now I cannot get it up (enough)

 

[mac_1103]

7 grams per liter should give you between 2.4 and 2.5 volumes of CO2. That may be a bit high for some English styles but it's not outrageous or anything. It's your beer, carbonate it the way you like to drink it.

I still think you should weigh the sugar to be sure. Also, why such a hurry to bottle? Another week or two in the fermenter would probably improve the beer anyway, and two gravity readings a couple of days apart with no change means that it's done fermenting and you shouldn't have to worry about bottle bombs unless you add too much priming sugar.

 

[bobtheUKbrewer2]

Mac - So why am I getting so little carbonation ? One additional piece of info, my last 25 kg sack of crushed pale malt was very fine - could this be relevant ?

 

[DBhomebrew]

What kind of bottles? I'm thinking insufficiently crimped crown caps, rubber gaskets on fliptops that are hard or cracked. Or the bails are too loose.

 

[bobtheUKbrewer2]

flip tops and crown corks and PET - leakage definitely not the issue - you are up early LOL

 

[mac_1103]

If the bottles are sealed properly then either you're not be adding as much sugar as you think you are or things are actually working the way they should but you just like more carbonation. Again, use a calculator and weigh the sugar. Try splitting a batch with different amounts of priming sugar in different bottles. Swing top bottles can handle up to 4 volumes. PET bottles can go up to 10. When you use PET bottles they should get very stiff after a few days.

 

[bobtheUKbrewer2]

thanks Mac I do have very accurate scales and 10 heaped teaspoons of sugar was between 68 and 69 grams.........

 

[mac_1103]

One other thing that has an impact (but not a big one) is the temperature of the beer at the end of fermentation. Priming calculators take into account the CO2 already dissolved in the beer before you bottle. Colder beer will have more CO2 and warmer beer will have less (e.g., 1.01 volume at 15C, 0.86 at 20C, 0.76 at 25C).

 

[VikeMan]

Mac - a heaped teaspoon of corn sugar is 7 grams.

For brewing purposes, any sugar should be weighed rather than measured by volume. Corn sugar, especially so, because it's so compressible. If you google weight per volume of corn sugar, you may notice that estimates vary significantly.

Also, "heaped" is a fairly non-definitive measure of volume.

 

[ncbrewer]

I wonder if you're actually getting poor head retention, making it seem like low carbonation. Could be something as simple as glassware that's not "beer clean". I know I don't go to great lengths cleaning my glasses - just run them through the dishwasher.

 

[bobtheUKbrewer2]

ncbrewer - glasses and jugs are rinsed in hot water after use and before use - never dishwasher - never tea towel ( a thin cotton towel used to dry stuff after washing up) = (hot water and liquid soap in a bowl for washing glasses plates cutlery after a meal)

 

[hotbeer]

How and when you perceive the low carbonation might be important for others understanding of your issue.

The first time I bottled beer, I filled them all the way to the top and had probably a millimeter or two of headspace. When I opened them, there wasn't any pffft sound. I thought they were flat and that idea clouded even my taste perceptions. It took awhile to do away with. Eventually I realized there was a decent amount of bubbles coming out of the beer in the glass and that it was actually good and well carbonated beer.

I've found that bottles need about 2 or 3 cm to give a good pffft sound when the top is popped. I use crown caps though. Don't know what swing tops or corks bring to that.

Another time I thought I had poor carbonation but it turned out to be the beer was too cold at opening time. As my it warmed up in the glass to a more proper drinking temperature, the bubbles coming out of solution were more apparent.

I don't consider head retention to be any indication of whether a beer is carbonated.

 

[bobtheUKbrewer2]

hotbeer the present issue is PET bottles are not firming up as they usually do

 

[mac_1103]

PET bottles are not firming up as they usually do

So wait, the same process has given you good results before? Might have mentioned that sooner. How many times did it work and how many times has it failed? You need to figure out what has changed, even if you're sure that nothing has.

 

[bobtheUKbrewer2]

at least 20 years with PET bottles, before then 2 pint cider bottles with bakelite screw in stoppers. Honestly, the only change is very fine crush on my last 25 kg bag of pale malt, same strengths, same yeast, same hops, same sugar - thanks all for trying.......

 

[doug293cz]

at least 20 years with PET bottles, before then 2 pint cider bottles with bakelite screw in stoppers. Honestly, the only change is very fine crush on my last 25 kg bag of pale malt, same strengths, same yeast, same hops, same sugar - thanks all for trying.......

Highly unlikely that crush could affect the carbonation process, especially if your fermentation was normal. In-bottle carbonation is just continued fermentation after adding some additional fermentable sugar. If you got a reasonable FG, then your wort was adequately fermentable, and there was nothing in it that would inhibit fermentation. Maybe it's something as simple needing more time to carbonate, especially if your conditioning temp was a little lower than normal. It's going to take longer to carbonate at 17°C than at 22°C.

Brew on