Issue with Belgian Triple (WLP 530) - Over-Carbonated Bottles

[Luxo_Aussie]

G'day All,

I've come across an issue with a Belgian Triple which I fermented with WLP 530. Recipe (for 21L) was 6Kg of grains (mostly Weyermann extra pale pils with a bit of vienna & carahell), mashed fairly low with steps of 15@52, 30@62, 30@67 & 20@72 hopped with Styrian Goldings with 850g of candi sugar added at flame out.

Fermentation was two weeks in primary, two weeks in secondary. However, I thoroughly over-pitched (onto entire yeast cast from earlier batch) and then went on to stress out the yeast in the primary by fermenting at about 24 degrees. The Krausen exploded out the airlock as well, epic mess! OG was 1083, FG (at bottling) was 1012, tested over two days.

Bottling was back in May, dextrose bulk priming to reach a CO2 volume of 2.7. I have noticed that all of the bottles have been over-carbonated (not quite gushing but foam escapes the bottles after pouring half) so I did a side-by-side tasting next to Westmalle Triple last night. Mine was very close to the commercial, albiet mine wasn't as good, had rougher flavors and just less refined overall. I tested the FG and it was now 1007!

It doesn't appear to be a bottle infection as there's consistency with the over-carbonation across bottles there's no off flavors. It also appears that this might be an issue with another beer (Belgian Strong Dark) which used the same yeast, same over-pitch, same mess and was stressed out in the same way. I'm trying to work out the root cause of this problem; if it was not enough time for WLP 530 to fully ferment, stuck fermentation towards the end due to stressing the yeast or other reasons, an infection somewhere along the line or something else. Does anyone have an idea what might have happened here? Any insights greatly appreciated!

Cheers,

Tristan

 

[Brewman_]

Bottled her too early I think Tristan.

Gravity less than 10 is what I would expect.

 

[The Mack]

I've had 530 work very slowly to finish, and although two weeks in primary should be plenty (let alone the two in secondary) I've found a little extra time in secondary is beneficial for Tripels.

 

[Luxo_Aussie]

Bottled her too early I think Tristan.

Gravity less than 10 is what I would expect.

You're 100% right. This was my first AG where I mashed low so was happy with 1012 when bottling. Since then I've begun to anticipate the FG more accurately based on the mash. I was hoping four weeks in the fermenter would have been enough but will keep this in mind for the future. Would it be worthwhile re-pitching healthy yeast towards the end of the fermentation of high gravity batches to ensure that it's been 100% successful, or not worth the bother?

I'll burp & re-cap these bottles over the coming weeks to see if they can be salvaged, does anyone have an idea how many burps might be needed for 5 gravity points of error (1012-1007)? Fully aware that this depends a bit on bottle headspace, but I'll probably start with twice and go from there...

Cheers!

 

[riichiee]

What sort of bottles did you use? You might might have some fairly dangerous bottle-bombs on hand. If they are just the regular glass bottles (not the heavy bottom Tirage seal, or plastic bottles), I would proceed with caution. Take care when moving them, as a dropped bottle that is that carbed is bad news.

Each gravity point fermented in the bottle is equal to 0.5 C02 levels. If you were off by 5 points, you've got an extra 2.5 CO2 levels in there, giving you a total of 5.2.

Honestly, they are probably lost at this point. Most likely you won't be able to open a bottle without it foaming over.

 

[Luxo_Aussie]

I've used Euro-Style 500ml bottles from Augustiner Helles (https://www.ratebeer.com/beer/augustiner-lagerbier-hell/9604/) - they are fairly common in southern Germany but rare in Australia. They seem fairly sturdy for the most part but I've noticed that the caps have started to bend outwards from the pressure!

I've been burping a test sample from the affected batches for the past couple of weeks by lightly easing off the cap without opening it and then recapping. I haven't had any beer come out yet from this technique. It looks like about 5-7 burps per bottle are going to be needed to get these to where they should be but will need wait awhile to make sure. I'll update concerning tastings once everything has settled.