A lot of us tend to concentrate on grind size, ratio, quality of beans and technique when we brew our coffee. All of these variables are very important to ensure that you get the best cup possible. I think we tend to forget one aspect that could possibly be the most important: water temperature. The temperature of your water can ultimately change your brew.
We all know that good quality water is the main ingredient that makes our coffee taste like liquid gold. Water temperature plays a big part in brewing because if you are running your water too hot we run the risk of over extracting leaving your coffee tasting bitter. On the flip side, running your water too cold runs the risk of under extracting which makes your coffee taste sour and weak. Both of these make for an undesirable and unbalanced cup.
Through educational research the recommended temperature for manual brewing is between 90.5°C - 96°C (195°F - 205°F). This range sometimes gets confusing because people think it's the temperature of the water itself. It's actual the temperature of the water once it hits the coffee (slurry). The reason why we brew in between these temperatures is because it's where the water soluble flavour compounds easily dissolve. Brewing within this range will give you the best results. The boiling point for water is 100°C (212°F) so this gives home brewers an understanding of where we need to be. I normally let my kettle rest for a minute or so before I pour it into my pre-heated Monarch Kettle.
The best way for you at home to control your water temperature is to probably buy a thermometer or spend more and buy a temperature controlled kettle. This will give you full control of your brew.
Remember that water temperature can drop dramatically when it hits something cold. It's important to pre-heat any vessels or directional kettles that you might be using. This probably sounds a little over the top but if you have spent money on great equipment and time thinking about brew methods why shouldn't you take water temperature seriously? Coffee needs water, so I think you should take it a little seriously.
Check out this awesome video from Verve Coffee. If you haven't seen it, it's well worth a look and gives you a basic understanding about water temperature.