How to make Mushroom Ketchup

Mushroom Ketchup and Ingredients with vintage cookbooks

I had never seen or heard about Mushroom Ketchup until I moved back to Scotland as an adult with my own family. It was once a “fashionable” condiment! Touted as the secret ingredient responsible for the success of rich gravies produced by Victorian cooks. As soon as I tried it, I realised it could be the perfect umami booster for plant-based and vegan sauces and soups. While it was readily available in Scottish supermarkets, I’m now back in New Zealand there isn’t an equivalent available, so I had to learn how to make mushroom ketchup for myself.

Flicking through my bookshelves, I discovered that I had three traditional recipes in my collection of 1940’s cookbooks. All from books I had inherited from my Scottish Granny. 

Unlike the product we purchased and enjoyed, traditional recipes are a thin liquid, but that actually contain a good quantity of mushrooms. (Supermarket versions sometimes have as little as 3% mushrooms.) Living near one of New Zealand largest mushroom producers definitely helps, but you don’t need large perfectly flawless mushrooms.

My recipe is a combination of the vintage recipes I found in my Granny’s cookbooks, it makes a rich Mushroom Ketchup, a small amount will enrich any plant-based soup, sauce or stew. 

Mushroom Ketchup

  • 1.5kg large flat mushrooms
  • 40g seasalt
  • 300ml spiced vinegar
  • 250g (1 medium onion) peeled and diced

Spiced Vinegar

  • 300ml malt vinegar (see GF option below)
  • 3g (1tsp) black peppercorns
  • 2g (1tsp ) each  allspice berries, cloves and  ground ginger
  • 6 dried bird’s eye chillies


Day 1

Rub the dirt off mushrooms with a clean cloth or tea towel. Dice or blitz the mushrooms (stems included) in a food processor.

Layer the mushrooms in a bowl, sprinkling the sea slat in-between layers. Cover with a clean cloth and set aside for 24 hours.

To prepare the spiced vinegar – add all the ingredients to a pot and bring to the boil. Remove from heat and put a lid on the pot, leave for 24 hours.

Day 2

Strain the whole spices from the vinegar and discard.

In a heavy based pot, combine the spiced vinegar, diced onion, mushrooms and any liquid released from salting the mushrooms.

Bring to the boil, put a lid on the pot (to prevent too much evaporation) and simmer for 2 hours. Check and stir every 20 minutes or so.

Remove from heat and cool for 10 minutes.

Strain through double cheese cloth or a nut bag, squeeze out as much liquid as possible.  Return the mushroom ketchup to the stove and bring to the boil again. Pour the hot liquid in to sterilised bottles and seal immediately.

This recipe makes 400-500ml.

Allergy Friendly Option

This recipe contains malt vinegar, which is usually made from barley but can also be made from rye – both grains contain gluten. To make a gluten free mushroom ketchup replace the malt vinegar with white wine vinegar. For extra richness you could use 250ml of white wine vinegar with 50ml of balsamic vinegar.

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