Like Obsidian, I cook the beer down a lot. I use half water and half beer syrup, so the liquid is "all beer" or even more.
I open a couple of containers, pour them into a pan, and simmer away for awhile. I then cool it or freeze it. I don't have them sit around anywhere getting flat, I just cook it.
I also will add a cube or two of beer to any soap I'm making, into the water that the lye goes into.
I highly recommend having the habit of doing the lye in the sink, or at least for new additives.
I open a couple of containers, pour them into a pan, and simmer away for awhile. I then cool it or freeze it. I don't have them sit around anywhere getting flat, I just cook it.
I also will add a cube or two of beer to any soap I'm making, into the water that the lye goes into.
I highly recommend having the habit of doing the lye in the sink, or at least for new additives.