Sensor value +1 in iOS push notification

So I use a motion sensor in a beer can chute to my basement that drops beer cans in a crate. It counts the cans and a php script records the values.

I’m using a scrape sensor to get the value. When I drop a new can in the chute, I want to be made aware of the value of the scrape + 1. Here is what I have, but its not working:

automation 85:
- alias: "Another Beer on the Wall"
  trigger:
    platform: state
    entity_id: binary_sensor.beer_cans
    from: 'off'
    to: 'on'
  action:
    service: notify.iOSApp
    data:
      message: "{{sensor.beer_today +1}} Beer Today"

I know its small, but I was hoping to get a little help with the message line. It doesn’t seem to fire at all.

Cheers