We’re back with our blog series, in this week’s post we will be covering:
- What grinding and conching is, and how these processes were first discovered.
- The different types of machinery that can be used to grind and conch chocolate.
- How we make sure our chocolate is silky smooth every time.
He had mistakenly discovered grinding and conching. Grinding is the process by which cocoa beans are ground into a chocolate liquor. Chocolate liquor is essentially 100% cocoa nibs ground down into a liquid state. Conching means keeping the chocolate moving (or ‘agitated’!) for an extended period of time - removing any discerning flavours and delivering a beautifully rounded chocolate.
When our founder, Max, first began making chocolate he used an Indian spice grinder, more specifically, a Premier Wonder Refiner. This machine was able to produce 2 kilos of chocolate. Due to the Wonder Refiner’s petite size and its wheel to chocolate ratio, Max was able to get smooth chocolate in less than 24 hours!
There are many different ways of grinding cocoa beans, some chocolate makers use a ball mill. This is designed for milling chocolate via the friction between 6 to 8mm steel balls. The advantage of a ball mill is that it can generate 1000kg of cocoa liquor in 2 to 3 hours, however, the machine cannot conch the chocolate and so a separate machine is required for this. On the other end of the spectrum, the simple pestle and mortar can be used to grind chocolate, however you would need some serious patience and strength to manually grind the cocoa beans!
Max was committed to following a similar route to the Indian spice grinder, so he sourced a melanger to grind our chocolate. The melanger used in our chocolate factory is a ‘Cocoa Town’ which was sourced from America. This meant, instead of being able to conch two kilos of chocolate with the Wonder Refiner, the melanger had a capacity of 30 kilos allowing us to vastly increase production. In addition to this increased capacity, the machine is dual use. The Cocoa Town grinds the cocoa beans between two granite stones, releasing the cocoa butter and grinding down the mass - resulting in chocolate liquor.
Unlike the Wonder Grinder, the Cocoa Town melanger needs longer to grind in order to achieve smooth chocolate - around 72 hours! This is because the two granite stones are much larger than the predecessor. When loading the machine with cocoa nibs, it’s important to add little amounts throughout the day. You do not want to jam the wheels and put a halt to the grinding process.
When adding cocoa nibs, the machine generates heat through friction, however we increase the temperature by using two heat guns. This encourages the release of cocoa butter and quickens the time it takes for the cocoa nib to liquify.
After 24 hours of grinding, we are ready to add our unrefined cane sugar. We load this into the Cocoa Town melanger, a single scoop at a time, this is so that the machine has a chance to grind the newly added sugar particles. The granite wheels in our Cocoa Town grinder move in a way that stirs the chocolate liquor in a figure of eight. This keeps the chocolate from spilling over the sides, and it also quickly and efficiently incorporates the unrefined cane sugar. Which prevents it from settling on the sides of the machine.
Because chocolate is composed of butter and no water at all, the sugar doesn't dissolve. So, it’s imperative to get the sugar loaded early in the process to allow it time to grind down. More often than not, if a bar isn’t smooth it’s because the maker has not given enough time to grind down those sugar particles.
Another way we make sure our chocolate has a good mouthfeel is by monitoring the amount of cocoa butter which is released from the ground cocoa beans. When grinding, heat is generated, and the dry granular consistency of the cocoa nib is turned into a liquid state as cocoa butter is released. Depending on the bean/origin we’re working with, some have a good amount of natural cocoa butter, however for the beans that do not, we add additional deodorised organic cocoa butter to ensure we achieve our desired consistency.
We are determined to make sure all of our chocolate meets our high standards, so we check that each batch has ground properly using a scientific approach. We check the ‘micron’ count in our chocolate. A micron is a unit of measurement and a single micron is one-millionth of a meter. When making chocolate, we’re concerned about the micron count as we want the particle size to be between 20 and 30, so that the chocolate is smooth, not gritty and has a good mouthfeel.
We use our grindometer to check our chocolate’s micron count. This instrument is used to measure the size of particles in suspensions, such as inks and paints. To use the grindometer, we take a small blob of chocolate from our Cocoa Town and place it at the top of the channel. We then use a palette knife to scrape the liquid chocolate to the end of the steel instrument. As the chocolate’s colour changes from dark to light, the particle size is indicated. When the chocolate stops filling in solidly, the number which it is next to, shows the micron size.
Our melanger not only acts as a grinder, but also a conch. This period of agitation is imperative to ensure the cocoa butter is equally distributed. It also helps develop flavours through frictional heat, releasing volatiles, acids and oxidation.
The longer we conch our chocolate for, the more we can dissipate undesirable, intense flavour notes. This, along with our attention to detail when sorting and roasting means we can remove any flavour notes that will not sit well in the bar.
After grinding and conching, we unload the chocolate into gastronorm trays.
As the chocolate is not in a tempered state, the speed of which it cools down, affects the particle size as it sets. We have found that the slower the chocolate cools, the bigger the crystals are. Because of this, the chocolate reaches a powdery state. This is effective for blitzing and making hot chocolate as the pieces have a fast melting point.
In our experience, the longer you leave the untempered chocolate, the more flavours can change over time - known as ageing or maturing. If we were to temper and mould chocolate immediately after it has been conched, sharp flavours and inconsistencies could be found. We have discovered that maturing the chocolate for a minimum of 3 weeks gives the chocolate a rounded edge and allows us to effectively showcase the bean’s flavours, with a good consistency across that particular harvest.
Good things come to those who wait! These steps take time, but we hope that our process is reflected in our finished bars. Using the cacao that we work with and putting it through these steps allows us to achieve very distinct flavour notes. If you’ve not yet tried them, explore our online store and bite the Bullion to see for yourself.
Once we have successfully ground, conched and aged our chocolate, we are then ready to temper it! We’ll be looking at this step, next Sunday in #BehindTheBar. To read it on Friday 21st (before general release!) make sure you have signed up to our mailing list via our website footer!
We’re interested to know:
- Did you know that the texture of smooth chocolate was discovered by accident?
- A pestle and mortar could be used to grind chocolate?
- Do you know of any other bean to bar chocolate makers that mature their chocolate for longer?