How hard should we press down when capping?

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One Life Brewing #lifeistooshortforcrappybeer
HBT Supporter
May 22, 2018
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Minnesota Finnish territories
Yes I looked through quite a few pages on capping but this never really was addressed. I use an Agata bench capper and the caps push hard and then seem to slip into place. Do I push down then real hard or since it has already seated and feels like the bell has slid down is it good enough?
That's something they never really explain. Has it crimped in once the bell has slid over? I put small dents/smiles in a few caps and think I was pushing too hard.
You'll get a feel for it. I agree that the dent is a sign of too much pressure. It should be smooth, when you feel it slip into place you are home.
When I first used mine I had it on a low table in front of me and felt like I had to push down very hard from that angle. But when I moved so that I was positioned more above it, and pushing down from that angle, it was much easier and required less force.
I'm of the mind that getting the dent in the cap is fine, I push down until you "feel" it crimp and then I push a bit more just to be safe, most of mine are dented. I've busted 2 bottles and bottled around 200 now. As others have said you will get a feel for how the capper physically lets you know the cap is on there.
Gradually increase pressure on the lever until the cap crimps into place. Hold this pressure for a second or two. You won't need to increase pressure. It is like using a dead blow hammer. You strike but hold instead of letting the hammer spring back.

Make sure the capper height is correct for the bottle so the pressure applied goes to the bell assembly rather than the body of the capper.. I use vinyl discs to raise some shorter bottles in height between the click adjustments on the capper. I have the old one with the height adjustment button.

I have the same capper with the push button. I set my capper similar to yours so that it would not touch the bottom of the slot. Due to living 100 miles from the nearest home brew store I also bought a Red Barron capper as a backup since they only cost $11 online. I had practiced with it and did not dent but then again i did not press as hard as when capping filled bottles.
A few years ago I decided to push down real hard to make sure I was getting a good seal. Not having any problems - just improving the process. ,I started getting lots of flat beer. I backed off to the normal force and no more flat beer. More isn't better. I think I was deforming the cap seats. Just push until you feel it seat.

Also, my instructions say to lubricate the bell. I found out the hard way that they mean it. I use paraffin wax on the inside of the bell.
Just trying to picture in my mind how a crown cap actually works. Coming from the sheet metal die world, I think in terms of cross sections. The top of the cap is already the right diameter to fit the bottle. The corrugated rim is too large. When the bell (the punch) comes down, it forces the corrugations smaller, gripping under the lip of the bottle (the die), compressing the plastic insert and sealing the bottle. The corrugations provide enough rigidity that the metal doesn't spring back and loosen the seal.

So far, so good. Now, if you continue to press the little magnet thingy into the top of the cap, that force is working to break the seal, as if you were using a bottle opener at all points simultaneously. When you retract the capper bell, the springback will now try to loosen the cap.

Therefore, in my visualization at least, you want to avoid denting the top of the caps. My antique bench capper has nothing at all in the bell, it works very well.
It's not about the force, just push it enough to bend the cap properly around the edge of the bottle neck and no more. The capper (and the structure of the cap itself) should take care of the proper seal. Using excessive force could be dangerous and all the different cappers are not necessarily able to withstand that.
Use as little pressure as you can. My cappers will require quite a bit of force to begin and then they suddenly seat. That is plenty.

I recently got some oxygen absorbing caps. I don't know but this batch of caps are much harder to crimp than others. Thicker metal? Can't wait to use them all up but I bought 3 packages of a 144 caps each. 7 or 8 more batches.....