I use the Reflex 15kg kitchen/postal scale for all my coffee and measuring needs. There is an accompanying Baking Scale app that has a speaker function with a fully editable voice, tons of unit options, and is generally usable with mild button labeling issues in iOS. Here's the Amazon link:
$1Worth noting that the scale itself doesn't speak, it's all done through the app, and you will need some sighted assistance to add tactile dots on the Power and Tare buttons since they are placed in a touch surface rather than using tactile buttons. Once you have it set up, it's super fast and works so much better than all the blind-specific talking scales out there, and the fact that I can have the "speaker" in the app set to the same speed as VoiceOver really helps keep things quick and efficient.