[cooki]

how long do i have to boil sugar syrup so that it reaches 238 degrees?
(i don't have a candy thermometer... )

[momoreg]

It depends. It depends on the temp of the water you start with, the strength of your flame, the conductive properties of your pot, and how much you're boiling.

There's a way of testing the sugar by hand, which involves dipping a small amount of your boiled sugar into a glass of ice water. The resulting texture of your sugar (soft ball) will determine if your sugar is ready.

[Erik]

You can also use a spoon if you are not up to dipping your fingers in 200+ degree pots

[cakerookie]

Get a candy thermometer.. Best way to be sure.