Newbie Question: Cap Diameter

My second batch turned out semi-flat and I’m looking for answers because the first batch turned out excellent in all regards. Details:

• Cooper DIY kit received last Christmas.

• First batch was Cooper Dark Ale placed into PET screw-top bottles. Great taste, lots of carbonation. Per instructions, used 2 of the Cooper carbonation pills in each 22oz bottle.

• Decided to buy an antique, cast iron, Meyer capper off Ebay just because I like old things. What a steal at $9.

• Second batch was Cooper Lager that came with the kit. Wort percolated for 3 weeks. Everything looked great. Decided to use my capper. Got new brown 12oz glass bottles and new caps from the local brew store. Sterilized bottles with a washer/spritzer and placed them on a red tree stand to dry. My brewing room is not heated so I can’t be absolutely sure the StarSan was fully dry, but they dripped for 2 hours on the drying tree. Capper worked great.

• 3-4 weeks later the bottles are very low on carbonation and there is just enough head to cover about 3/4 of the surface in a standard 3-1/2 inch beer glass. This is consistent from bottle-to-bottle.

Prime suspect is the capper because every aspect of sanitation, brewing temp, water, yeast, was done as carefully as a former R&D engineer could muster. Same lot of carbonation pills, instruments, etc as first batch.

Just wondering if the die on the capper is worn and not completely closing the cap. My installed caps measure 1.145" across the sharps of the teets. Thinking here is that a smaller diameter would mean the cap is drawn down lower (tighter) onto the lip.

Or maybe Cooper Lager is just a flat beer ?

Want to get this worked out before batch #3, an expensive Mountmellick brown ale, comes rolling out. Any insights would be appreciated.

Did you add sugar to prime your finished beer? I assume so, but maybe it wasn’t well mixed. That happens from time to time with newer brewers. Just need to rack into the sugar solution to assure a good mix.

:cheers:

You mentioned your brew room isn’t heated. What is the current temp? If it is too low the beer won’t carb up As the yeast won’t eat away at the priming sugar. Try moving them to a warm room (at least 70°) and flip the bottles daily to keep the yeast in suspension.

Measure the diameter of the seal material inside the cap and compare it to the outside diameter of the bottle mouth. Standard American caps are 26mm to 26.5mm. Some European bottles take 29mm caps. Some of the older German bottles seem like a 25mm cap would be best. You didn’t mention your location. (My mistake. You are in USA.)

When you are capping do you meet resistance and then the bell snaps down to seat the cap? If it doesn’t the bell may be worn.

[quote=“ynotbrusum”]Did you add sugar to prime your finished beer?

[/quote]

Yes, thanks. The exact same product and batch that was used on the first brew that turned out well carbonated.

Now that’s an idea. I placed them on the concrete floor several weeks ago when things were hot-ing up here in Atlanta, thinking that it would soon be too warm. Several days later it turned cold again and temps haven’t really recovered. The room is hugging a constant 55F.

I’ll move the bottles tomorrow to a warmer area and see.

Great tip. Thanks.

[quote=“flars”]Measure the diameter of the seal material inside the cap and compare it to the outside diameter of the bottle mouth. Standard American caps are 26mm to 26.5mm. Some European bottles take 29mm caps. Some of the older German bottles seem like a 25mm cap would be best.
[/quote]

All my bottles are 26mm. That’s been checked.

[quote=“flars”]When you are capping do you meet resistance and then the bell snaps down to seat the cap? If it doesn’t the bell may be worn.
[/quote]

Lots of resistance during capping, and the die does finally come completely over the cap and bottom out inside the die.

But the capper did arrive with a lot of rusty scale inside and out that had to be media basted off. (So much rust that it put off all the other Ebay bidders.) That’s why I was wondering if the die was now oversize and not enabling a good seal.

Thanks.

55° isn’t going to cut it. The yeast needs to consume the sugar to creaet CO2.

Wanted to get back with a progress report.

The problem was indeed the lower temperature. The capped bottles were placed back into my warm fermentation cabinet for 10+ days at 68F and the yeast started working again. Now all the bottles, large and small, pour with a nice thick head and have a delightful tingle in the mouth. The carbonation really changed the entire character of this beer.

Can’t thank everyone enough for their help. I was so sure this batch was going to need to be poured out. You’ve saved the day.

:smiley: