How quickly does sugar change hydrometer reading?

[jonereb]

I needed to add more sugar prior to pitching yeast to get the hydrometer reading to 1.090. How quickly can I measure sugar after adding it? (BTW, I dissolved the sugar before adding it.)

 

[A_McG]

As long as the sugar is completely dissolved and stirred up well, the reading is immediate.

 

[jonereb]

Good. I got the reading I wanted. I dissolved the sugar, stirred it in, and waited 4 hours.

 

[bernardsmith]

It's instant - Your hydrometer reads the density of the liquid. You add sugar, you increase the density. It's a purely mechanical tool - no chemical process is taking place.