Temperature Control

We make cheese, for the most part, by the addition of bacterial starter cultures. These bacteria are living entities and do a specific job of consuming lactose and creating, as a waste product, lactic acid. This requires us to consider temperature for two reasons, the first being keeping the bacteria alive – a wide temperature range – the second being a focus on their productivity, which is a narrow range of temperatures at which bacteria are most efficient at lactic acid production.Our most vital piece of equipment to help us regulate temperature is, of course, the thermometer. There are many of them on the market and it is not a tool that you need to get from a specialist cheese kit supplier. It’s best to use a thermometer that can clip onto the side of the pan if using a dial type. Digital thermometers tend to give a quicker read out so a clip is less essential, but having one means you can use it ‘hands free’ which is a benefit.The temperature range used for cheese making is quite narrow, so a thermometer that ranges from 0C to 100C will be suitable The more important feature your thermometer needs to have is 1C / 2F marker points because to make good cheese we do need to control the temperature of our milk or curds to an accuracy of 1C.

You will need to calibrate your thermometer before you first use it and then periodically after that, especially if you ever drop or knock it. Calibration makes sure that the reading your thermometer gives you is the accurate.There are two ways of doing this which both involve using water of a known temperature, i.e. at boiling and freezing points.We can use the fact that water freezes at 0C or 32F to calibrate our thermometer. Fill a bowl with crushed ice and then with cold water. Mix well and leave for five minutes to ensure an even temperature. Place your thermometer spike in the iced water and take a reading. If you are reading 32F or 0C then you should be fine, if not, follow your manufacturer’s instructions to reset the read out (usually an adjustable nut on the back for dial thermometers, or a reset button for digital) so that it does read 0C or 32F when it’s in the ice bath.To use boiling point for calibration, bring a pan of water to the boil on your hob. Once bubbling, its temperature will be 100C/212F (this is at sea level, every 1000 feet above sea level boiling point drops by 1C, e.g. it’s 98C at 2000 feet). Insert the thermometer into the boiling water and take a measurement. Again, adjust your dial based on the reading you take – please do this safely away from the boiling water though and recheck afterwards.

Once calibrated, your thermometer is ready to use in your cheese making exploits. Probably the biggest challenge with temperature control in our kitchens is finesse. Many recipes require very gradually temperature increases, say 1C every five minutes, and almost all of them specify a period of time where the curds have to be held at a certain temperature (see why), which can be a full hour or more.There are really three distinct methods for heating milk gradually, and each has pros and cons. The simplest, and the one I advocate when starting on a cheese making journey, is to use the smallest hob ring on your cooker at the lowest heat (I do this on the soft cheese video). You may even find that this is slower than required, especially if using a gas or induction hobs, and if that’s the case, just turn the heat up a fraction until you’ve achieved the heating rate required. I don’t recommend using this method for electric rings as they are just not responsive enough when you need to alter the heat.The second method, and probably the one written about the most when it comes to cheese making at home, is to use a form of double boiler. The benefit of this method is two-fold, firstly you’re not applying direct heat to your milk/curds removing the risk of burning, and secondly, temperature changes to the milk or curds are much more gradual and gentle.To set up your own double boiler either place your milk pan inside a larger pan containing water (which I find quite a fiddle) or in the kitchen sink filled with water of the required temperature. I have used the sink method on a number of occasions and find it to work very well – although when using my 20lt pot, there is very little room for water to surround it in the sink.

Altering the temperature using the double boiler method is simply done by adding hot or cold water, as the case may be to the sink or larger pan. Using this method you will probably find it is much easier to hold a temperature for a longer period of time, but that it can be quite tricky to manage gradual temperature increases.

The third method is to use a Bain Marie, which is a professional double boiler. They usually take the form of a pan or tray for your cooking contents – milk, in our case – and then an outer skin that contains water. The Bain Marie is plugged into the mains and a temperature selected to apply to your milk or curds. The water in the outer skin is heated to the required point, which then heats the milk in the pan. The advantage of these is obvious, fingertip control with great accuracy. The disadvantage is cost – an electric Bain Marie that holds 20lt of milk could cost £100 or more.

All three methods work well. Using direct heat from the hob is simple, but needs care; double boilers are more tricky, but deliver gentle heating and hold temperature really well; and, Bain Marie are expensive but the best tool for highly finessed temperature management.