Low Gas on Last Four Batches - What's Going Wrong???

Syracus

My last 4 batches have been sweet and low in gas. See attached file. Primary fermentation goes really well at the start, then it seems like the yeast is stalling/dying at the end of primary fermentation. I've tried stirring it up, and all of the following but I'm running out of options, I could do with some help if anyone knows a possible solution.... cheers.

I'm using a Coopers kit, with plastic bottles, which I sterilise and rinse well each time.

Ingredients: It's basically been the same, Coopers Wheat Beer, I've tried different suppliers, and the use by dates are all well in the future

Sanitation: I thought I was pretty good with this. I switched to a no rinse one last time, Starsan, just to try something different, no luck.

Temp: My initial investigations pointed to this. In a bid to keep this constant at 23 deg. I got a PID controller with PT100 temp sensor, and brew belt. I used this last time and confirmed with a temp data logger that the twmp remained with + and - 1 deg of 23 Deg.

I am stuck. If I'd wanted to drink sweet flat beer I'd have bought a load of Budweiser.....

BeerNut

I'd consider those normal finishing gravities for kit beers. How are you priming them?

matrim

As BeerNut said those gravity readings look ok and are consistent with what I've brewed myself.

For the flatness are you sure you're priming with enough sugar before bottling? How are you priming and how much sugar are you using?

I use something like http://www.tastybrew.com/calculators/priming.html to help determine the amount of sugar to use when priming

Syracus

matrim wrote: »

As BeerNut said those gravity readings look ok and are consistent with what I've brewed myself.

For the flatness are you sure you're priming with enough sugar before bottling? How are you priming and how much sugar are you using?

I use something like http://www.tastybrew.com/calculators/priming.html to help determine the amount of sugar to use when priming

BeerNut and matrim, I'm using carbonation drops to prime, recommended at one drop per 500mls PET bottle. The beer is definitely sweet, so it doesn't seem to be getting used up. (This was the same amount used on the 'Excellent' result batches).

I also read on the forums to just leave the bottles, they sometimes take longer during secondary fermentation. However I've left for around 5 or 6 months with no appreciable difference in gas amount. The bottles open with a small pffffsss sound, and only get a head if I long pour, with the head only lasting a couple of minutes.

I'm going to try another batch soon, but I have the definition of insanity in mind, i.e. doing the same thing over and over again and expecting a different result.

BeerNut

If it's not getting used up you'd see the sugar stuck to the bottom of the bottle. It seems unlikely, though. I'd be concerned about the bottle seals and maybe switching to a different format.

Syracus

BeerNut wrote: »

If it's not getting used up you'd see the sugar stuck to the bottom of the bottle. It seems unlikely, though. I'd be concerned about the bottle seals and maybe switching to a different format.

I just checked, for secondary ferm, it works out at 4.2g of sugar (27% glucose and 73% Sucrose) per drop (60 drops in a 250g bag). Interestingly, the rate was originally 2 drops per 750mls bottle, but, coopers included a note to recommend that one drop is sufficient for 500mls.

I might get six new PET bottles to try in the next batch, to rule this out. As Sherlock would say... Eliminate the impossible and whatever remains, however improbable, must be the truth.

Thanks for input BeerNet, I've read a lot of your posts, impressive!!

howamidifferent

I use 2 carbonation drops for those 500ml PET bottles.
I found using one left the beer flat.

tteknulp

BeerNut wrote: »

If it's not getting used up you'd see the sugar stuck to the bottom of the bottle. It seems unlikely, though. I'd be concerned about the bottle seals and maybe switching to a different format.

Yes i agree , i use swing tops and find them very good

Syracus

howamidifferent wrote: »

I use 2 carbonation drops for those 500ml PET bottles.
I found using one left the beer flat.

Thanks, will do also in a control group in next batch.

Matrim, I checked out that link re amount of suger, very interesting, cheers.

3dsteel

What temperature are you leaving the bottles to carbonate? You should leave the bottles in a warm place (19 - 23°C ish) for the first 2 weeks to let the yeast eat the priming sugar. If they are too cold the yeast might be dormant?

Edit: BTW, I use 2 carb drops per 500ml bottle too, but one drop should be fine if you leave it long enough.

Syracus

3dsteel wrote: »

What temperature are you leaving the bottles to carbonate? You should leave the bottles in a warm place (19 - 23°C ish) for the first 2 weeks to let the yeast eat the priming sugar. If they are too cold the yeast might be dormant?

Sorry, I never mentioned this. For the last two batches I wrapped them in an electric blanket, and used the PID controller to keep them at 22°C. For 2 to 3 weeks.
Ironically, the previous 'Excellent' result batches, I just wrapped in blankets, and they turned out fine.

BeerNut

I'd definitely recommend buying a 4-pack of Flensburger (the weizen is nicer than the pils) and including the fliptops in the experiment.

I've done loads of kits using one carbonation drop per Coopers PET bottle and have always been very happy with the results: good sparkle and excellent head.

Lovely Bloke

Recently we've started to up the carb drops to 2 per 500ml.

We found that using just 1 was not sufficient. Opened the first bottle with 2 drops in it last weekend and it was much improved.

Syracus

BeerNut wrote: »

I'd definitely recommend buying a 4-pack of Flensburger (the weizen is nicer than the pils) and including the fliptops in the experiment.

I've done loads of kits using one carbonation drop per Coopers PET bottle and have always been very happy with the results: good sparkle and excellent head.

Yep I'll try it. An excellent reason to buy a 4-pack of beer if ever there was one. Do you know where I can get Flensburger weizen, Tesco?

I'll give the two drops a go also, in a small control group also, no harm in trying it.

Thanks for the direction. I think I may have been getting a bit fixated with the FG's, but happier now you think they are normal enough.

BeerNut

Syracus wrote: »

Do you know where I can get Flensburger weizen, Tesco?

Don't think so. You'll need to go to your local beer specialist. There are plenty of other German half-litre fliptops, but Flensburger is usually cheapest at €10 for a four-pack.

If you're in Dublin, go to the Bull & Castle Beerhall and ask for empty fliptops. They always have loads, free to home brewers.

matrim

BeerNut wrote: »

If you're in Dublin, go to the Bull & Castle Beerhall and ask for empty fliptops. They always have loads, free to home brewers.

I know where I'm going later this week

Syracus

BeerNut wrote: »

Don't think so. You'll need to go to your local beer specialist. There are plenty of other German half-litre fliptops, but Flensburger is usually cheapest at €10 for a four-pack.

If you're in Dublin, go to the Bull & Castle Beerhall and ask for empty fliptops. They always have loads, free to home brewers.

Yes, in Dublin, nice tip, thanks BeerNut. I'll have a look for Flensburger also just to give it a try.

Syracus

Embarrassingly late follow up to this thread, apologies, but I would like to post results of that experimental batch I ran.

I have in fact only just finished the last bottle of that batch.... it's been a very busy year! So the last of the votes are in, here are the results...

5 x PET 500ml Bottles with 1 priming drop: Low gas, although there was 1 or 2 that were borderline acceptable
10 x PET 500ml Bottles with 1.5 priming drops: All excellent
10 x PET 500ml Bottles with 2 priming drops: All excellent
5 x Glass 500ml flip-top Bottles with 1 priming drop: Low gas, although again there was 1 or 2 that were borderline acceptable
10 x Glass 500ml flip-top Bottles with 2 priming drops: All excellent

I think it pretty clearly shows that the problem was insufficient priming drops. There may have been other variables that had some small influence in the outcome but the main factor points to the priming suger.

A fairly simple solution, in hindsight of course:rolleyes:

Thanks for your help everyone, the forum was a great help, and continues to be...:)