Dextrose.. Is it slower to carb than sugar,

[Truman42]

I usually prime my bottles with brown sugar but bulk primed with dextrose on my last batch.

First time I've bulk primed BTW. And used a priming calculator to get 2.0 volumes of CO2.

It was an oatmeal stout and after 16 days they are still only slightly carbed.

Now I know 16 days isn't a long time but in this current weather my sugar primed bottles were almost fully primed within a week.
Is it just that dextrose takes longer or could I have underprimed them?

 

[jaypes]

Which calc did you use? I usually use a few and compare the numbers. First time i bulk primed i undercarbed as well. I used one with a temp entry which threw me as i dudnt know if this was the temp the beer fermented at or at time of bottling

 

[mwd]

I don't bother with bulk priming calculations coz I can't be bothered I use between 150 and 160g sugar/dex for a 23l batch.
Up here in the tropics they carb up in a week tops. I would not have thought there would be any significant difference between dex and sugar.

 

[Truman42]

I used this one here

http://webspace.webring.com/people/ms/sirleslie/AlcoholChart/PrimingCalculator.html

But I did cross reference it with another one. From memory I used 80grams dextrose for 15 litres of beer. Calculated on the highest fermentation temp reached which was 20C.

 

[mwd]

Sounds good you should get a decent level of carbonation with 80g.

 

[bum]

You don't mention how you added the dex. Since it is the first time you've done it I wouldn't discount the possibility of operator error.

Did you dissolve the priming sugar first? How certain are you that you've got an even mix throughout the the batch? If you've copped some bottles that don't have enough priming sugar you'll also have some that have too much. Caution is the word of the day.

 

[Tony]

I used to use 140 - 150g dex in 22 liters when i was making 23 liter batches and bottling. Worked perfect.

I used to disolve the dex in about 200ml of boiling water and tep it into the racking wort.

Leave them another couple weeks and try one...... it may pick up a bit more.

cheers

 

[Truman42]

I put the dex into a pot and covered with water. Brought it to the boil for a few minutes then cooled and poured into an empty fermenter.

I then racked to the fermenter making sure the beer swirled the dextrose solution. Then I also gave it a gentle swirl with a spoon.

I guess I'll just have to wait a bit longer. Just wondered if it was a dextrose thing compared to sugar.

 

[bum]

I doubt it. I've used white sugar, caster sugar and dex and never noticed any difference in time. Temp seems to be the only thing that makes difference for me.

 

[Bridges]

Probably not as expert as others on this site. I've only ever used caster sugar or dex into bottles with no problems or noticable difference between the two.

 

[manticle]

No.

 

[Tony]

I remember many lost brain cells ago when i started brewing, i had nothing but trouble getting consistent carb in by bottled beers.

There was bugger all in the way of on line help and i was recording every little datail of my beers progress. I had a suspician that the FG of the beer had more of an effect on carb, than ferment temp as is used in a lot of priming calculators. I plotted all my beers FG's and bulk priming amounts on some grid paper and marked over, under and properly carbed beers.

This gave me a rough line that i made through the middle, and a bit of maths gave me an X factor to calculate the priming amount depending on the beers FG.

It worked perfectly and all my beers were perfectly carbed for years to come!

I will note that i have always used Dextrose, and the figures were done to give a good carbonation after about a month in the bottle. I was not a fan of using a lot of priming sugar to have it carbed in a week. This usually resulted in over carb, big bubbles, metallic tang from CO2 and poor head retention. I preferd a slower carbonation with smaller bubbles and a fine head.

I gave the spread sheet i will attach to a mate starting brewing to bulk prime a FWK he made, and it worked out perfect. After 14 days it was still a bit flat and he rang me saying..... what do i do..... its still half flat. I said " leave it for a week to 10 days and try it again. A week later it was perfect.

For a 22 liter batch of beer finnishing around 1.008, i would prime with 150g of dextrose for a rate of 6.82 grams per liter.

You used 80g in 15 liters which works out at 5.33 grams per liter

about 22% less.

I would say leave it for another couple weeks and if its still a bit lacking, that is all you will get.

next time use the g/L rate on the document i have attached to work out how much to use and give it a try.

I used to make sure i bottled the beer at room tamp also. I found if i bulk primed and bottled cold, i got inconsistant results, usually over carbonation, because the beer holds some CO2 in solution from fermentation while its cold, especially lagers that have putted away slowly in CC.

cheers

View attachment PRIMING CHART 1.xls

 

[Truman42]

Thanks for the chart Tony, sounds like you got it sussed and I will give it a go with my next batch.

I CC at 2C and have always bottled at this temp. Any reason why I can't drain 19 litres to the keg then leave the fermenter out on the bench overnight to warm back up to room temp and bottle the rest the next day so I'm bottling at room temps?

 

[Truman42]

This beer finished quite high 1.021. (Lazy Irish ale yeast). So according to the chart I should have primed with approx 68 grams for 15 litres.

I did try to rouse the yeast and used the usual techniques.

I mashed at 69C as I wanted it to be sweet. It was an Oatmeal stout.

Mouthfeel and taste is good and carbonation is ok for the style I guess just seems under primed ATM . But It also loses co2 quickly and you have to force a head when you pour it.

Will see how it looks in another couple of weeks.

Thanks gents.

 

[jyo]

I haven't used the Irish ale yeast, but if it behaves anything like wy 1968 (which can be a lazy bugger) , maybe it takes a while to carbonate?