The best replacement for water bath is pressure canning.

The best alternatives to water bath are rated as following:
★★★★★  pressure canning
★★★  pressure canner
★★  pressure cooker
★  heat block
★  incubator
★  bain marie
★  steam canning
★  steam bath
★  oil bath
★  canning
  steam bath canners
  pressure cooking
  hot plate
  pressure can tomatoes
  pressure cookers

Your alternative for water bath is not listed? Suggest!
Speaking about water bath, one probably shouldn't forget about springform pan.

Other search terms related to water bath and their ratings are:
★★★★★ springform pan
★★★ cheesecake
★ test tube
You have in mind a companion for water bath and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of water bath in all years. Click on graph for more.
water bath
pressure canning
pressure canner