A steam bath (Figure 1.49) is a relatively safe way to heat flammable organic liquids. They are designed to heat beakers, Erlenmeyer flasks, and round-bottomed flasks, and have a series of concentric rings that can be removed to adjust to the size of the flask. Many science buildings have in house steam lines in their labs, allowing for this convenient and safe method to heat various solvents.
The steam line should be connected to the upper arm of the steam bath, and condensation should be allowed to drain from the lower arm of the bath to the sink (Figure 1.50a). The steam tap should be adjusted so that a moderate amount of steam can be seen coming only from the central opening in the bath, then a flask should be set atop the opening to warm the flask (Figure 1.50b). Steam should only warm the bottom of the flask, and steam should not be visible coming out anywhere else in the bath. When warming highly volatile solvents, the flask may need to be held above the opening of the bath to control the rate of heating (Figure 1.50c), or the steam rate lowered.