Is the parasite mode of a DS18B20 less power consuming than the normal mode?
What average power consumption do you get in parasite mode and what in active mode? Just do the math. 

Be aware, that the DS18B20 is charging an internal capacitor for voltage buffering when beeing in parasitic mode, so I don't think you will reduce power consumption with it (also the datasheet suggests to drive the dataline with a FET to strong HIGH during aquisition to deliver enough current).  

Some rough calculations:
With a standby current of the sensor of 1µA the consumption is neglectable in comparison to the ESP. During these 750ms of "unnecessary" on-time the ESP is drawing as much energy as the sensor is drawing during 15,000s (more than 4 hours).

Again, it depends on how often you are going to take measurements. If you measure only once a day, parasitic mode will safe you some power. If you measure once a minute, I guess not.

// Oh, I somehow did not see you specified \$f_S \$ with once per minute. In this case, I wouldn't bother using parastic mode.

But anyhow: Even in deep sleep your ESP is drawing 20µA. This means, if you get rid of the additional 1µA from the sensor your stand by consumption will go down by only 5%. Not worth it, I think.