i have home brewed for 35ish years and the best advice I can give is DONT sterilise your equipment or bottles.
Regardless of how well you rinse your gear - there is always a slight residue/aftertaste.
I only wash my gear in hot water after use and I rinse my bottles in hot water and store upside down in crates.
The only downside is hot water washing does seem to make micro pits in the plastic vat that makes washing harder so I replace it every 5 years.
I learnt this from a uncle in Stokes valley that home brewed in a dirt floor garden shed with cobwebs in roof.
Could you clarify where you think this after taste comes from?
I am confused by your comment about rinsing not getting the taste away.
Most folks here will be sterilising with sodium metabisulphite, potassium metabisulphite or Campden tablets which are a mix of the two.
You are not supposed to rinse after using those and I find it hard to believe that these will cause any noticeable aftertaste.
I wonder if you are referring to the use of some form of detergent to clean the equipment.
For cleaning, I use Chlorinated Tri-Sodium Phosphate which is sold by the brew-shops as pink bottle wash or the like. That is a very effective cleaner and it rinses away very readily. It is widely used in the food industry because it does not leave residues. You would not use it to do the washing up as it is less effective against fat but it sure cleans everything to do with brewing. The kind of detergent that you would use to hand-wash your dishes will not rinse away so well.