Training – building a cob oven for your community growing project

10984499_930591937004996_7353564795669304592_nThis summer  Tyfu Pobl held a free two day training course at Denmark Farm Conservation Centre, near Lampeter,  on how to build a cob oven.  As a result the farm now has a fully functioning and beautiful oven to add to their list of alternative technologies! Mara Morris, coordinator at Denmark Farm wanted to build a cob oven on site ever since she took over the rein, and with the help of FCFCG and a successful crowd funding campaign, Mara and the farm’s dedicated team were able to turn this dream into a reality.

The training day was run by Matthew Lloyd of the Fabulous Cob Oven Company. Matt’s teaching style was very hands on; as soon as we were gathered on the first day we ‘set to’ and worked to complete the stone plinth for the oven. Denmark Farm’s volunteers had built a dry stone wall for the oven to be built on to. On inspection, the wall was slightly too small than the recommend 3ft cooking height. To
rectify this, participants went on a ‘bottle hunt’ around the site. When we’d raided the various recycling bins, the bottles were used to form an insulation layer in the base of the wall with gaps packed with a sawdust and clay mixture. Once the base was 3ft high Matt laid the block pavers, which formed the oven’s cooking area and instructed us to get our feet out to start cobbing – mixing the clay and sand by standing IMG_6020(or dancing) on it! To make the cob we mixed 1 part clay with 2 part sand. Denmark Farm had bought in some clay for this purpose; however Matt commented that he generally uses the sub soil he finds on site to create the cob mixture. A common mistake when making cob is to make the mixture too wet. The finished texture should be like apple crumble topping or short crust pastry before you add the water. To get the consistency for the cob right, you can also try the ‘drop test’. IMG_5997This is where you drop a ball of cob onto the floor from knee height. If, when dropped the mixture resembles a cow pat, there’s too much water in the mix, similarly if the ball crumbles more water should be added.

IMG_6011Whilst half the group were perfecting their ‘twist’ actions to make the cob, the other half were building a sand former. The sand former is essentially a dome template for the cob to be formed around. Once both layers of cob have been added the sand former is literally scraped out of the oven. By the end of the first day our hard work paid off as we’d successfully completed the plinth, the sand former and the first layer of the oven.

Whilst the first day of the training was bright and breezy the second day, which coincidentally, was the first day of summer was inclement and tempestuous. IMG_6066The driving rain didn’t dampen our spirits and we continued to make cob regardless, with the more intrepid taking their shoes and socks off whilst donning macs and woolly hats. The weather proved to be problematic where the cob was concerned. Unfortunately the sand that we had been using had been left out in the rain and was making the cob mix too wet. We managed to use the boiler room in Denmark Farm’s fabulous Eco-Lodges, which worked a treat. With a fresh batch of cob made the second layer was ready to be built and by lunch time it had been formed.

IMG_6095In the afternoon Matt cut out a door for the oven using lollipop sticks to reinforce the opening. He then lit a fire in the entrance of the oven to help dry the cob out. The initial plan was to have pizzas for lunch; this didn’t quite work as planned due to the overall wetness of the cob. Due to Matt’s perseverance the first pizzas came out at around 6pm after various attempts to get the fire going in a wet oven. They were well worth the wait!

IMG_6111Mara and the team at Denmark Farm used the oven to feed visitors attending their open day on 20th June. There are also plans afoot to build another cob oven in the Eco camping area in the autumn. If you weren’t able to make it to the course in May check out Denmark Farm’s website for more details.

One of the course participants shared a great recipe for Haw ketchup for use as pizza base topping, which all you keen foragers might light to try:

To make Haw Ketchup you will need;

  • 750g haws (hawthorn berries)
  • 450ml vinegar
  • 100g sugar
  • 25g salt
  • 1tsp freshly ground black pepper
  • A pinch of ground allspice
  1. Take the top and bottom bits of the haws, then put into a saucepan with the vinegar,
  2. Simmer for half an hour or until soft,
  3. Allow to cool enough to handle, then pass through a jelly bag,
  4. Return to the pan and add the salt, pepper, spices and sugar,
  5. Boil for 10 minutes then pour into sterilised old sauce bottles.

2 Responses to Training – building a cob oven for your community growing project

  1. Gwen Alun July 21, 2015 at 10:31 am #

    Good morning,

    Are there any upcoming events/training in North Wales?

    Kind regards


    • Jim Groves July 21, 2015 at 10:36 am #

      Hi Gwen – there is a study tour going to Hulme Community Garden Centre in Manchester next week:

      Have you signed up to the Tyfu Pobl newsletter? We put out monthly updates on training and events happening in North, Mid and South Wales. With your permission I can add you to the mailing list 🙂


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