Tucked under the railway bridges at Peckham Rye, behind red wrought-iron gates –formed of what look like repurposed railings, bars, and all sorts of odds-and-ends – you’ll find the craftsmen at work in Blenheim Forge.
Jon Warshawsky and James Ross-Harris made their first knife as an experiment after watching YouTube videos. That doesn't sound like a promising start, but – along with engineer Richard Warner who joined the pair in 2014 – they now make knives sought after by the world's best chefs.
Blenheim Forge knives are handmade using Japanese knife-making techniques that traditionally take decades to learn from a master. Yet Richard thinks that their biggest advantage is that they've been able to explore the craft by themselves. They have had no one telling them what to do. The team is constantly testing their own skills, and developing new techniques every single day.
Choosing a santoku, the favourite all-round knife
A santoku is the Japanese style all-purpose kitchen knife. The name translates as ‘three virtues’ or ‘three strengths’. However no one knows for sure which of its many virtues this refers to.
Perhaps it is the ease with which it cuts through the three main ingredients – fish, meat, and vegetables – in Japanese cuisine.
It could be the knife’s suitability for three different cutting styles – mincing, slicing and chopping.
Or perhaps it is because this one knife can perform many of the duties of the three traditional Japanese knives – the yanagiba (fish preparation), the deba (filleting & skinning fish and meat) and the usuba (slicing vegetables).
Whatever the reason, the santoku is the chef's favourite blade.
Unique knife blades hammered from blue paper steel
Blue paper steel takes a razor-sharp edge easily, and retains it for a long time before it needs sharpening again. The knives are formed from layers upon layers of blue paper steel, heated until soft and hammered together.
Once polished you can see the rippling layers – the patterns of loops and whorls formed during forging are unique to each knife, and as well as being beautiful are a visible testament to the work that goes into making them.
Blue paper steel is so-called because the manufacturer, Hitachi Metals, wraps this type of carbon steel in blue paper. It isn't actually blue! The steel has small quantities of chrome and wolfram added, making it more resistant to corrosion and chipping.
Once polished you can see the rippling layers – the patterns of loops and whorls formed during forging are unique to each knife
A vital part of making a knife is heat processing. Once the blade is shaped, it is then heated and quenched to harden and temper the blade.
This is done from the bottom edge upwards to ensure the cutting edge hardens first, but timing is important – if the heat in the top of the blade is allowed to warm up the bottom again the structure of the knife can be compromised, leading to a blade that could be too brittle or too soft. Done correctly, you end up with a hard blade that can be sharpened to almost nothing and glides through ingredients.
Evolution of a knife, starting with the first piece of steel on the left, through to the finished (but not yet polished) blade on the right
Hardwood handles from PEFC certified sustainable sources
Once they had the blade-making process down, it was time for the Blenheim boys to perfect the handles. They started by sourcing wood from a local cemetery, but soon looked for other avenues when the process of sawing all the wood themselves started to take time away from the forge.
All the wood they use comes from sustainable sources and is PEFC certified. They choose hardwoods, unlike their Japanese counterparts. “There’s a different culture here in the West. In Japan, if a knife handle wears out they go and get it replaced. Over here, people think it’s shoddy work,” explains Richard.
But the choice to use hardwood goes beyond durability – heavier hardwoods lend a reassuring weight to a finished knife, making them a pleasure to hold and use. The finishing touch to the knife handles is a ferrule – a ‘cap’ that protects the wooden end of the handle from splitting.
Hardwoods lend a reassuring weight to the handle of a finished knife, making them a pleasure to hold and use.
Unlike Blenheim Forge's classic dark-handled knives, the limited edition Sous Chef x Blenhiem Forge Santoku Knives have a ferrule made from sustainably sourced buffalo horn capping pale bird’s eye birch wood.
The bird's eye birch is so called for the small, swirling lines that interrupt the natural grain of the wood, forming distinctive ‘bird’s eye’ patterns.
Caring for your knife
Such a piece of craftsmanship does require a certain degree of care.
The purity of the steel makes the blades reactive, so immediate cleaning is advised if the knife is used to cut acidic foods such as lemons.
This also means the blade will build up a patina with use, becoming a record of your cooking journeys. To best preserve the cutting edge, avoid using the knife to cut bones or other hard, brittle ingredients and use a plastic or wooden cutting surface.
Wipe the blade clean as often as you can during food preparation and dry thoroughly immediately after washing. Store the knife in a clean, dry area to prevent rust. A scouring pad can be used to remove small areas of rust that may occur, as well as to help maintain the finish.
If the knife is going to be stored for a long time without use, we recommend lightly oiling the blade – camellia oil is particularly good, but any non-reactive plant-based oil will work.
If you can easily make it to Peckham, you can get your knife professionally sharpened at the forge. Otherwise, it’s recommended you use two flat grindstones or Japanese whetstones to keep your knife in top condition – a 1000 grit stone to sharpen and remove any fatigued metal, and a 3000 or 6000 grit polishing stone to hone the blade to a keen edge.