I’m bottling maple syrup.
What's stuffed in the bottle? Jam you bottled for later! How could you forget?
This word consists of the on'yomi reading for 瓶 and the kun'yomi reading for 詰 that you learned when you learned 詰める. You've learned them both so as long as you remember the rendaku, you should be able to read this word too! Just remember that 詰 is taking the め from 詰める with it in this word too. You can't see it, but it's there.