Operating the Drafts of a Wood Cookstove: The Point of Diminishing Return

When we first installed the Margin Gem, one of the aspects of operating the stove that was significantly different than the Qualified Range was the amount of time needed for the wood to ignite when adding wood to an established fire.  Then, once the fuel ignited, it didn't seem to burn like it would have in the Qualified.  Thus, I would open the drafts of the Margin Gem until I felt like the fire was burning the way I thought it should.

Well, I'm embarrassed to admit that basically, I spent the first three years of operating the Margin Gem quite inefficiently.  I remember telling my mom that I thought the Margin Gem was a real wood eater.  What I've come to understand in the last couple of years is that the Gem shouldn't have nearly the amount of air that I was giving it in order to reach peak heat output.

A Little Background Information-

With the Qualified Range, once the fire was established, I would operate the stove with all drafts completely closed unless I was having trouble keeping the fire burning because of wet wood or something like that.  Our kitchen chimney draws extremely well, and the Qualified, though a very well made stove, was not airtight, so plenty of air was constantly being pulled in to the fire even with the drafts tightly shut.  Thus, fires always seemed to burn brightly in that stove.

You can see that the two drafts on the left side of the Qualified
are closed while the stove is cooking our Thanksgiving Dinner
in 1999.

Enter the Margin Gem-

The Margin Gem cookstove is equipped with two drafts.  The primary or direct draft is located in the ash cleanout door below the firebox.

The secondary air-jet re-burn draft is on the left side of the stove.  For more information about this draft, see this post.

When I first start the stove, I usually open both drafts widely.  However, the secondary draft can usually be sufficient by itself, so sometimes I only open it.  As the fire catches and begins to burn hot, I always shut the direct draft completely and then just operate the stove by adjusting the secondary draft.

Thus, during the first couple of years of using the Margin Gem, I would often leave the secondary draft open as much as a quarter of an inch, trying to get the fire to behave the way that I was accustomed to seeing it in the Qualified.  My thinking was that since the Qualified was not airtight, it must have been permitting a lot of oxygen to get to the fire even when the drafts were completely closed.

What I've come to believe is that the Margin Gem actually operates at peak efficiency when the secondary draft is opened enough to let air in but not enough so that you can see any gap between the knob and the air intake shaft.  Once the fuel has caught fire, this seems to allow sufficient air for combustion, but it keeps the stove very hot and the fuel is not consumed so quickly.

The Point of Diminishing Return-

You might be questioning my use of the phrase "the point of diminishing return" in the title of this post by now.  You see, conventional wisdom would lead one to believe that the more oxygen that is allowed to get to the fire the faster it would burn and, therefore, produce more heat.  (I believe that this is indeed the way a coal fire would operate, but someone should confirm that in the comments below.)  However, what I've come to understand is that if the drafts are open too wide--past the point of diminishing return--the abundance of room temperature air that is allowed to flow through the stove actually cools everything down.  This results in having to burn quite a bit more fuel in order to provide enough heat for cooking and baking.

This "point of diminishing return" will potentially be different for every stove, every chimney, every type of wood, and even every weather condition, so it is the job of the wood cookstove cook to constantly be observing and evaluating the way the stove and fire are behaving in order operate the wood cookstove at peak efficiency.

In any event, I no longer think that the Margin Gem is devouring more fuel than necessary in proportion to the amount of heat that she puts out.

What methods for operating the drafts of your wood cookstove do you use?  Let us know in the comments below.

The Best Laid Schemes o' Mice an' Men Gang Aft Agley

Well, my last post ended up being a little pre-mature.  We had the stove fired from Wednesday, the 28th to Monday, Oct. 3rd.  I had planned to work on cutting wood after school that Monday, but my brother had other plans.  He had a bunch of alfalfa hay down, and we were due to get quite a bit of rain the following day, so I ended up helping him put up hay instead of cutting wood.  That meant that I had to let the fire go out and restart the electric water heater.

The rest of that week ended up being quite wet, so it wasn't until Friday, the 7th, that we ended up starting the stove again.  Marjorie has been our sole source of hot water since then.  She has been busy cooking and baking too.

Now to get down to more important posts!

And We're Off! The 2016-2017 Heating Season Begins

Tonight, after cleaning the chimney, stovepipe, and internal flue chambers, Marjorie cooked my supper and is now heating our hot running water again.  The electric water heater has been turned off for its 7-8 month siesta, and we are back in business!

Last year, the electric water heater was turned off on Sept. 30th, so we're about right on schedule.  Our thermometer has registered temperatures in the 30s for the last three mornings, and I would have liked to have started the stove earlier, but we've had so much rain (nothing like the flooding in northeastern Iowa, though) that all of the wood was very wet around here.  I also hadn't taken the time to cut any wood yet.

Today after school that changed.  And what a banner afternoon it was, too!  The weather was beautiful, the chainsaw started on the first try, and the wood splitter did the same.  I felt like a king.

I have lots to share with all of you, so let's all hope for a schedule that permits a good deal of blogging over the next few months.

Happy autumn, everyone, and may your wood cookstoves be burning brightly soon!

Caramelized Onions on the Wood Cookstove

It's been a hot summer here, in my opinion.  Really hot.  The last fire that we had in the cookstove was on May 6th, but we had a cool day last Friday, and I couldn't resist the urge to cook on wood again.

We have a beautiful row of Walla Walla onions in the garden, and Nancy loves bratwurst, so it seemed a good idea to have brats with caramelized onions.  Making good caramelized onions involves quite a long cooking time, so it is a great side dish to make on a wood cookstove.

Start with about two teaspoons of olive oil.  For this, I like to use a non-stick frying pan.  To start the onions cooking, place your pan directly over the fire. 

I apologize for the quality of this photo.  I didn't have the flash on the camera turned on.

The olive oil heating over the firebox.

Add onions that have been sliced about a quarter inch wide.

I took advantage of the fire by cooking several things at once
to be refrigerated for later.

 

Stir the onions around a bit to get the oil distributed, then cover the pan right away to begin cooking them quickly.

Keep an eye on the onions, stirring them occasionally.  Once they have become limp, remove the lid.  Also move them to an area of lower heat.

Stir occasionally until they are fairly evenly browned.  This can take quite a bit of time.  These onions cooked for a total of about an hour.  Because it is summer and I didn't want the fire to last a long time, I was letting it die down, so I ended up moving the onions back over to the fire.  Once they are all brown, add a scant teaspoon of sugar. 

 

Continue cooking gently for a while until the onions are reduced to a delicious-smelling, but slimy-looking, mess.

 

Serve very warm over bratwurst on a bun.  Delicious!

Marjorie Has Been Wandering!

After the cleaning the stovepipe and chimney after the chimney fire that I mentioned in the last post, I had quite a time reconnecting the stovepipe.  It was not damaged or changed in any way, but I just had difficulty getting everything connected properly, but I finally managed it.

However, last week, the stovepipe kept coming apart where an elbow and straight piece join.  Now, I know that screwing the pipe together would have solved that, and for longer runs of stovepipe, installing three screws at each joint is a requirement, but they have never really been necessary in our installation.

I completed another cleaning on Saturday morning, and had a TERRIBLE time re-installing the stovepipe.  After further investigation, I discovered that Marjorie the Margin Gem cookstove had actually migrated backward enough that the stovepipe was no longer able to line up properly.  Fortunately, we have some wiggle room in our rear clearances, or the movement could have been a big safety hazard, too.

I think that the reason for the rearward movement can be attributed to vibration from the floor as we walk by the stove or perhaps repeated force from the front of the stove as we fuel from the front lid or front door or as the oven door is closed. 

Whatever the reason, I wanted to record what had happened to us here on the blog so that others could benefit from what we've learned.  It pays to know exactly where your stove is supposed to sit so that if things don't seem right, you can check to see if the stove has been subtly shifting.

Be safe!

Chimney Fire!

I hadn't originally intended to write a post about this, but after further reflecting on the event and on the purpose of this blog, I'm hoping that by sharing our experience, someone else will benefit from our misfortune.  On a mid-February Saturday morning, Nancy and I were fortunate to wake up unscathed in our own bed.  We had a chimney fire in the night, and God was truly looking out for us because no damage occurred.  Here is what happened:

Like I always do each winter night, I had filled the Margin Gem's firebox with the largest chunks of wood possible.  Usually, I then almost completely close all drafts and dampers so that the fire burns slowly all night long.  This assures us of a nice bed of coals to rekindle in the morning, a tank of hot water for our morning showers, and fairly steady heat being emitted in the kitchen all night.

On that particular Friday night, I loaded the stove and then thought that I'd leave the drafts and dampers open for a little while to let the wood ignite better before shutting everything down.  Unfortunately, my forgetfulness kicked in, and I went to bed without shutting anything.  Thus, the firebox was completely full, and the stove was wide open.  This was clearly operator error, and I'm duly embarrassed.

I awoke in the wee hours of the morning to go to the bathroom and thought I'd run downstairs and put some more wood in the stove.  I sometimes do this when I know that the fire has had time to burn down enough that there will be room for another piece of wood.  When I opened the stairway door into the kitchen, I could immediately tell that the kitchen was much warmer than it ordinarily should have been.  This was due to the fact that the fire had burned so rapidly--not due to the chimney fire.  When I removed the front lid over the firebox, I was shocked to see that only a few coals remained on the grate where normally there would have been a lot of coals and some as-yet-unburned pieces of wood.  That is when I investigated and noticed that the draft, the oven damper, and the chimney damper were all open.  I still didn't know that we had had a chimney fire at that point, though.

When I began to rekindle the fire by putting a few pieces of wood on the coals, I immediately noticed that the stove was not drawing correctly, and then I became aware that every time I opened a lid, a little noise came from the stovepipe.  That was when I realized that we had had a chimney fire.  By that time, the wood that I had just put in the stove had caught fire, and there was sufficient draft to carry away the smoke, so there was not much that I could do except close the oven damper and the draft and let the fire burn itself out so that I could clean and inspect the flue in the morning.

Fortunately, we had cleaned the chimney and stovepipe during the first part of February, so there was not as much creosote accumulated in the flue as there might have been.  In my opinion, this is the major factor which kept this event from being a full-fledged disaster.  The other thing that helps us is our chimney.  The Margin Gem cookstove is vented through the masonry chimney which is original to our 98-year-old-farmhouse, but the chimney has been professionally sealed and lined with a heavy-guage stainless steel lining with quite a bit of space between it and the brickwork. Thus, there is an extra heat barrier between the structure of the house and the flue.

The next morning, I hurried to take the stovepipe down and sweep and inspect the chimney.  I didn't snap any photographs because I initially didn't plan on blogging about this event and I was in a huge hurry to get the fire going again because we had a ton of laundry to do and needed it to heat our water.

You might think that a chimney fire would burn away all of the creosote that is in the flue.  In my experience, what happens is that the creosote sort of bubbles and puckers so that it actually protrudes into the flue and impedes the draft.  It becomes sort of like the carbonized stuff on the floor of your oven after a pie boils over.  Because it is so brittle, it is easy to clean out of the chimney.

In my eighteen years of cooking with wood cookstoves, this is the second chimney fire that I have experienced.  Both events have some things in common: creosote, a hot fire, and an open oven damper.

The Margin Gem's oven damper in the open position.
It is the lower lever on the left with the black sphere on the bottom.

The first one occurred in the summer of 2004 (I remember this because Nancy and I were engaged).  I had baked bread in the Qualified on a late spring or summer afternoon, and after the bread came out of the oven, I opened the oven damper to let the heat escape up the chimney rather than heat up the house.  I knew that the chimney needed cleaning, but did not dream that a chimney fire would result.

All of this serves to remind me of a short quote from Gladys Dimock that Jane Cooper included in her 1977 book Woodstove Cookery: At Home on the Range: "Except for starting the fire, I always keep the oven damper closed.  This prevents the flames from going up the chimney and igniting any creosote.  We had a chimney fire once because the damper was left open.  Never again."

During summer use, I still open the oven damper when I'm finished cooking to let the heat escape up the chimney, but I'm careful about it.  Obviously, keeping creosote at a minimum is quite important too.

If you discover that you have an active chimney fire, the first thing to do is close all dampers and drafts on your stove because you want to deprive the fire of its source of oxygen.  This was sufficient to extinguish the 2004 chimney fire.

We keep a chimney fire extinguisher handy at all times.  This is a stick-shaped thing somewhat similar to a flare that is activated and put into the firebox.  I've never used it, though.

Another method for extinguishing a chimney fire which I've only read about is to put water-soaked newspapers on top of the fire in the firebox.  The idea is that the heat of the fire will cause the water in the papers to turn into steam, which will then travel up the chimney and extinguish the burning creosote.

If any of you have further information about chimney fires, please share it in the comments below.  We all should want to be responsible woodburners because operating our stoves safely results in fewer hazards and insurance claims, which in turn keeps us safe and our insurance rates low.

Popovers Fontaine

I love popovers!  I haven't made them in quite some time, but I decided to throw them together tonight since our chickens have been keeping us very well-supplied with eggs.

I wish I could remember where I got this recipe.  When I worked for the bank, sometimes I would be sent to work in the Avoca office.  I enjoyed substituting there because they had a break room where I could eat my lunch, and in that break room, they always had a stack of cookbooks that I would sit and peruse while I waited for my lunch hour to be over.  Thus, I know that I copied this recipe out of one of their cookbooks, but I didn't write down which one.

Popovers are extremely easy and fun to bake, and if you are a homesteader or farmer with your own chickens and dairy cow, you can produce most of the ingredients that you need by yourself.  Here is what you will need:

Popovers Fontaine

 

3 Tblsp. melted butter

3 eggs

1 cup milk

1 cup flour

1/2 tsp. salt

 

First, build your fire so that you will have a hot oven.  You're shooting for about 400 degrees.  Then, put the butter in a dish in the warming oven or on top of the reservoir (or wherever) of the range to melt.

 

The butter melting in the warming oven.

Grease 8 five-ounce custard cups and place them on a baking pan with edges.  I know that some people bake popovers in muffin tins, but I've never had very good luck with that, and using custard cups has never failed me.  You MUST put the cups on a pan.  Most of the shortening that you use to grease the cups will come out and dribble down the sides of the cups onto the pan.  You don't want that mess on the bottom of your oven!

 

 

 

Beat the rest of the ingredients together with a whisk.  Add the melted butter last.  The batter may look a little lumpy.

 

Fill custard cups half full of the batter.  Place in the oven until they puff up and are golden brown.  The recipe originally stated that they needed to be baked from 45-50 minutes.  I find that amount of time to be way too long.

 

 

 

I love to watch popovers bake.  You never can predict how they are going to look when they come out of the oven.

 

I always eat these with a little homemade pancake syrup, but I think that they would be good dusted with a little powdered sugar, too.  Fruit makes a great accompaniment for popovers.

 

 

 

My favorite memory surrounding this recipe is from the day Nancy and I were married.  My aunt and uncle stayed overnight here with me on the night before we were married, and so I baked popovers in the Qualified Range for our breakfast.  Just as we were sitting down to eat, my brother and my sister both arrived separately, so I ended up serving an impromptu breakfast for five that morning.  If you have unexpected company, these are an easy but novel go-to food.  I hope you enjoy them!