Inspect your petals and remove any debris or insects.
Place the brick in the center of the saucepan, and center the bowl on top of it.
Arrange the rose petals in the saucepan around the brick and bowl.
Pour enough water into the pan to cover the roses, keeping the water level no more than about an inch over the top of the brick.
Cover the pot with the convex lid upside down, so that the handle points inside the saucepan toward the bowl.
Bring the water and roses to a simmer over medium heat. Then adjust the heat to maintain a gentle simmer.
Set the bag of ice cubes on top of the lid. Keeping the lid cold will increase condensation as the steam from the roses rises inside the pot. This condensation is distilled rosewater, and will collect on the underside of the lid, dripping into the bowl.
As the ice cubes melt, pour off the water from the bag, adding new ice cubes before replacing the bag on the saucepan lid.
Let the rose petals simmer for about an hour. Be careful not to let the pot run out of water—the easiest way to do this is to be sure the heat remains at a low simmer. Once you’ve collected about 1 cup (240 ml) of hydrosol, turn off the heat and allow the pot to cool to room temperature.
Remove the saucepan lid and carefully lift out the bowl of hydrosol.
Transfer the rosewater to a sterilized bottle (use a small funnel so that you don’t risk spilling any of this precious liquid!)
Use the rosewater right away, or store it in the refrigerator for up to 6 months.