Saturday, January 19, 2013

Maintaining an Even Oven Temperature in a Wood Cookstove, Part 1



How the Oven on a Wood Cookstove is Heated



One of the most common questions that people ask me about cooking on a woodburning cookstove is how to maintain an even oven temperature.  I think that this question is so popular for two reasons: a) people have heard all manner of folklore about temperamental cookstove ovens and b) though it was once as common a skill as combing one's hair, people no longer have the foggiest ideas about how to control a wood fire.  Trust me when I say that baking in a wood cookstove is really not that difficult.  It is, however, a topic that is complicated to write about, so this is the first of a series of posts about how to manage the oven of a woodburning cookstove.

As with many aspects of cooking with a woodburning range, each experienced wood cookstove cook will develop a sytem which works best for him or her.  All I can do here is share what I know works for others and for me, knowing that each stove and chimney behaves differently than the next.  To begin with, though, it seems like it is necessary to first discuss how a wood cookstove oven heats.

As far as I know, what I'm about to tell you is true about all of the cookstoves being manufactured today with the exception of the the Vermont Bun Baker (or Baker's Oven), the Kitchen Queen, and Enterprise-Fawcett's reproduction Queen Cook.   The Vermont Bun Baker's firebox sits squarely above its oven, and from what I've read, the heat and smoke from the fire are routed down around the oven before exiting via the flue.  The Kitchen Queen and the Queen Cook are both designed so that their ovens are heated from the bottom.

The Vermont Bun Baker.  Photo from
www.vermontwoodstove.com


A drawing of the Kitchen Queen wood cookstove which
shows the flue path when it is in the baking mode.  Photo
from www.kitchenqueenstoves.com.

Enterprise-Fawcett's Queen Cook.  The
oven is the box at the rear with the nickel-plated
image of Queen Victoria on it.  Photo from
www.farmallclub.com.

To the best of my knowledge, all the rest of the woodburning cooktoves which are being manufactured today are designed in basically the same way.  Furthermore, this design has been standard in woodburning ranges since the last two decades of the nineteenth century.   From everything that I have seen or read about the new cookstoves on the market currently, the major differences between the stoves of today and the stoves of yesteryear are mostly due to adjustments in the fireboxes, draft systems, and cosmetic appearances.

Generally, the firebox is on the left side of the stove, and the oven damper is located in the middle rear of the stove just under the stovetop.  The oven damper is a little door which, when open, allows smoke and heat to travel in the most direct route possible from the fire and up the chimney.  When closed, the oven damper forces the smoke and heat to flow around the oven before exiting the stove, thus heating the oven.

The following picture is a scan of p. 283 of John Vivian's 1978 book entitled The New Improved Wood Heat, which was illustrated by Liz Buell and published by Rodale Press.  All of the wood cookstoves that I have worked with, cooked on, or fully examined (over a dozen) were configured in the manner illustrated in the top design.  The only difference is that the three cookstoves that I have cooked on regularly here at home--the Margin Gem, the Qualified, and the Riverside Bakewell--all have a baffle centered under the oven.  This baffle extends from the back of the stove to about half way to the front of the stove, forcing the smoke and heat to travel under the oven and toward the front of the stove before taking a left and traveling to the back of the stove and then out the stovepipe.


Liz Buell's illustrations from John Vivian's book The New Improved
Wood Heat.  The shaded strips represent the path that heat and smoke
take around the oven in a cookstove when the oven damper is closed.
The photos below show the oven damper lever on the left side of the Margin Gem, and the middle rear lid of the Margin Gem cooktop is removed to show the actual oven damper itself.

A picture of the left side of the Margin Gem.  The
oven damper lever is the one with the black knob
on the end of it next to where the top water pipe
exits the waterjacket.  When the lever is down like
this, the oven damper is open.

The Margin Gem's oven damper in the open position so that
smoke and heat can go directly up the chimney.


This picture from the post entitled "Perfect Roast
Beef from Your Wood Cookstove" shows the oven
damper lever in the up position.  This means that the
damper is closed and the oven is heating.

The Margin Gem's oven damper in the closed position, forcing
all of the heat and smoke from the fire to be diverted around the oven.

Now, we are very happy with the Margin Gem for many reasons, but one feature of the Qualified range that I miss is that it had a sliding oven damper.  The Riverside Bakewell range down in the summer kitchen is equipped with a sliding oven damper as well.  I prefer the sliding oven damper over the levered oven damper because you can decide how widely you'd like the oven damper to be open.  The following pictures are of the oven damper of the green and cream Riverside Bakewell in various positions.
Riverside Bakewell cookstove's oven damper handle in the "open"
position.

The middle "French plate" or "blank plate" is removed to show
the oven damper in the open position. 

The oven damper handle in the partially closed position.

The oven damper on the Riverside Bakewell partially closed.


The oven damper handle in the position "to bake."

The Riverside Bakewell's oven damper closed for baking.
The Margin Gem's oven damper is either closed or open; there is no in between.  While I do like the added flexibility and control of the sliding oven damper, it is important to note that I have not been inconvenienced at all by the Margin Gem's style of oven damper either.  Many old stoves were manufactured with the same style of hinged oven damper, and I've never read of anyone clamoring about it as much as I just have.  Furthermore, you can also see that when the oven damper is open, the hole that it creates is really not that large, so some smoke and heat still always travel around the oven to exit the stove.

I am surprised at the variety of places that oven damper levers are found on different woodburning cookstoves.  I've taken the liberty of drawing a cookstove with arrows pointing to the various places where I've seen oven damper levers placed.

Each arrow shows a location where the oven damper has been located on
wood cookstoves that I have seen.

Hmmmm.  I suspect that the aforementioned John Vivian might have artistic abilities which are about as poor as mine, thus causing him to have collaborated with Liz Buell for his book's illustrations.  I'm thoroughly embarrassed that all of you now know the limited extent of my talent in the field of visual arts.

The Waterford Stanley cookstove seems to have a pretty unique baffle and damper system which operates on the same basic principles as I have recorded here, but it is manipulated by using a lever in notched dials on the cooktop itself.  A good place to see how all of that works is at a website called Granny Miller.  You can see the article here.

Now that you know how the heat from the fire gets to the oven of a woodburning cookstove, stay tuned for posts on how to control the heat.

Quick Links:  Maintaining an Even Oven Temperature in a Wood Cookstove, Part 2 Variables

Maintaining an Even Oven Temperature in a Wood Cookstove, Part 3: What Other People Do

Maintaining an Even Oven Temperature in a Wood Cookstove, Part 4: What I Do

3 comments:

  1. this post was so informative-thank you

    ReplyDelete
  2. This post (and part 2) will be worth its weight in gold. I can't wait to read part 2.

    ReplyDelete