A log grate is one of the most important parts of any fireplace as it holds the logs up off the ground and lets air circulate underneath. Without air circulating, it’s hard to get a good fire going. The grate also allows ash and coals to fall through, and keeps the burning wood away from them. But when you shop, there are a few different kinds that you’ll need to consider. Cast iron grates are designed to be more suitable for charcoal burning. They can be used for wood and logs, but not very heavy fuel. Steel bar grates, however, are only suitable for burning wood, as the gaps between the bars are too big to hold coal, which would fall through.