Given the amount of trimmings or discarded bones are variable to each fish, we have written this recipe to represent percentages needed to produce any amount that you have. Up to 60 per cent has always been considered the loss of a round fish. Once the fillets are removed, even from 1 or 2 kg (2 lb 3 oz or 4 lb 6 oz) of the fish, there is still so much left.
We tried a number of different ways, some that failed and some that showed potential, but eventually one of our chefs, Tristan, discovered this recipe, which produces a stable fish sauce that can be made from just about any fish waste.
To produce the garum, start by adding 50 per cent of water to the total amount of heads, bones and scraps you have from small fish, such as sardine, mackerel, anchovies or trevally, then to this total quantity add 20 per cent of fine salt. Mix together, transfer to a mason (kilner) jar, seal and place in a circulator bath set to 40 degrees Celsius (104 degrees Fahrenheit). Leave for 7 days, stirring once daily. It is possible to produce a garum without a circulator bath but I would suggest investing in one if you intend to try to produce this sauce as fish waste can be temperamental. If you don’t have one, then use a sterilised mason jar and store in a dark place at room temperature, stirring every day. Make sure that the gall bladder is removed as it will make the finished sauce extremely bitter. This recipe is versatile and can be adapted to produce scallop, prawn (shrimp) or cuttlefish garums.
A note on my philosophy (and waste)
I don’t understand how the 40-45 per cent (or, more to the point, the 55-60 per cent waste) that chefs are taught to expect a round fish to yield can be acceptable globally.
Saint Peter is a fish restaurant in Sydney, Australia that seats thirty-four people in one sitting. In a working week we will purchase in excess of 150 kg (331 lb) of fish, that’s approx 25 kg (55 lb) fish a day. The average price for round fish in Sydney including the premium fish we buy is $20/kg. If we were to apply the industry standard yield expecations of 40-45 per cent then, at $500 a day, that’s a total loss of $300 and a yield of $200. Now I understand that bones are used for stock and some restaurants will be grilling the fish’s collar meat over charcoal but this only represents a small percentage of the “loss.”
For example, a 17 kg (38 lb) line-caught bar cod I bought whole at $24/kg cost me $408. Based on a 44 per cent yield, this represents a cost of $179 of “usuable” fillet. The other 56 per cent loss is seen as a cost of $228. The usable fillet weighs 7.45 kg (16 lb) and will yield 26 x 200 g (7 oz) portions that, to the eye, are desirable and worthy of their place on an a la carte menu. Each portion costs $15.69 and would need to be sold at a minimum of $60 in a restaurant to represent a “profitable” margin once overheads are factored in. To consider that if the efforts of this book only helped you gain a further 10 per cent of the “loss” you would have an extra 1.73 kg (4 lb) from that bar cod ($41.50) to play with.
In a small business this represents a huge opportunity to play your part for a more sustainable future, but also an opportunity to use more of what you are paying a premium for. It can be difficult to determine whether the additional labour it takes to dissect the fish into every single part and make it delicious is “worth it” from a financial point of view. One thing we have always found at Saint Peter is that when food costs go down, wage costs go up (and vice versa).
It is in recent years that I have focused all my energy into these “secondary” items. I was fortunate to be in a kitchen throughout my training that sourced a lot of whole fish every day of the week, so seeing the organs of the fish was part of a daily routine of scaling and gutting. There came a point though that I started weighing the offal that was removed from the fish and noticed some startling numbers. Some livers from john dory were equal to the weight of the fillet itself and roe from a mahi-mahi made up 12 per cent of the body weight. Not only was I looking at this as a product that had an actual dollar value, I saw so much potential in this offal to produce recipes from. I started with the obvious – salting roe to produce what was a primitive style of bottarga, before progressing to pan-frying fish liver simply with parsley on good sourdough toast (now a staple and favourite on the Saint Peter menu).
Also from The Whole Fish:
Excerpted with permission from The Whole Fish Cookbook, published by Hardie Grant, September 2019, RRP $40 hardcover.