Building Bertha, the woodfired oven.

Bertha is our woodfired oven. She lives in the SourdoughBaker Cafe, in West End, Newcastle. My mate Craig Miller and I designed her from scratch. There's more about that story on one of my blogs,  so I won't repeat it here. But if you are interested in SourdoughBaker Cafe, and it's oven, and other stuff, have a look at this blog too..

Bertha is a bit of a rarity - she's much bigger than a domestic woodfired oven (typically an AGA or Wamsler or even an Early Kooka), though she follows similar principles from a design perspective. She has two decks for baking bread, and a third below them which is effectively a 'heat bank'. There are two fireboxes at one side, one above the other. These fireboxes produce the heat for different parts of the oven. The top one heats the top deck and the cooktop, while the bottom one heats the lower deck. Each deck provides about half a metre deck space, upon which we can set up to twenty loaves or so at a time.

Most bakery style woodfired ovens have the fire set inside them, or are 'scotch' ovens, which have a separate firepit below the baking deck. Ours is a different beasty altogether, with a completely contained firebox joined to the baking deck. Thus, the heat travels via conducted means through brick, rather than via convection first, as is the case with the two ovens mentioned here.

To those of us who have not completed degrees in thermal engineering, having the heat enter the baking chamber via thermal mass, or conduction, makes for a whole different type of baking. The main feature of heating a baking deck using thermal mass is its steadyness - once the heat is in the deck, it stays there for a long time. In effect, we have been able to minimise the 'falling' effect of most woodfired ovens, making Bertha ideal for round the clock use.

But wait, there's more. As any old time baker will tell you, there's the crust. That's what this is all about. The crust produced via an oven with a large thermal mass is far superior to the crust from any other oven. Bread from a brick oven is just very special. You can get good crust in other ovens too - oil filled ovens, and gas fired setter ovens for example - but brick is a unique material with unique qualities. Hence, unique crust. Anyone who has eaten bread from a woodfired oven on a regular basis will be able to verify this.

I'll be adding to this article very soon, but for now I just wanted to give you a bit of a taste of my latest passion...