The Witches Kitchen

OK, so in The Bathroom Worth the 30 Years’ Wait, I promised the Rocket Stove Bath story. For Siobhanne and others who have asked, here it is.

For many years we had a star bath – a cast iron bathtub out in the open with a wood fire underneath it.  It had its charms, great charms – a clear view of a starry sky, a bath that stayed warm as long as you like, hot water from renewables even in the depths of winter.  But it also had drawbacks – the need to light the fire several hours before bath time, a fair consumption of firewood, no bath in the rain, or even after rain with a fireplace that got very wet, smoky fires, a bath that needed a deal of cleaning at the start of winter.

So the idea was to claim all the charms without the drawbacks, and the rocket stove bath has pretty well aced it.  It is under a roof and has walls most of the way round  but still a view of a starry sky.  Many of my best ideas happen while considering that sky.  It has a chimney that goes all the way along under it, which means the bottom is warm and stays warm for as long as you are willing to add a few sticks every half hour or so.  It is very frugal in its use of wood – a bundle of sticks that I collect from under gum trees along the roadside on my morning walk.  And it burns remarkably clean.

Rocket stoves are a classic design.  The essence of the idea is a vertical combustion chamber that is very well insulated.  Being insulated, it quickly becomes the hottest part of the system, and since heat rises, flame is drawn into it.  Being insulated too, it gets up to very high temperatures and burns all the volatile gases and smoke that cooler fires let escape.  The efficiency makes them ideal for cooking stoves in places where firewood is scarce and for space heating with wood fires in cold climates.

Being a classic design, there’s quite a bit of information around the internet about the basic principles but not much about using them in this application.  So this is my rundown on how we did it, and the things I think might be optional and the things that might be critical.

Step One:  The design

The critical dimensions for a rocket stove are critical.  There is a good explanation  at Design Principles for Wood Burning Cook Stoves that uses research by the lodestars of rocket stoves Dr. Samuel Baldwin and Dr. Larry Winiarski setting out the reasons.

For our purposes:

This is a diagram of the basic design.

• The diameter of the chamber that the hot gases flow through has to be the same all the way through the system.   Not necessarily the same shape, but the same size.  So the horizontal fire chamber, the vertical rocket chamber, the hot gas drop chamber, the chimney, all have to have the same area for the gases to flow through.  If you “choke” the gas at any point, it doesn’t work.  For example if you use a 6 inch pipe, it has a cross sectional area of 30 sq inches. All exhaust pipes, flues, etc after that can’t be less than 30 sq inches ( or it will throttle the gas trying to escape.)  You can use bigger, or smaller pipe in the burn chamber, and you then need to calculate the cross sectional area and make the flue pipes or exhaust pipe match that size.
• The length of the vertical rocket chamber (the long vertical bit) has to be greater than 3 times the length of the feed chamber and greater than twice the length of the fire chamber. So a vertical rocket chamber that’s is 900 mm high for example from top to bottom, can have a feed chamber that is less than 300 mm from top to bottom, and a horizontal fire chamber (the horizontal bit) that is less than 450 mm long.

We got a specialist plumbing supplier to make up our rocket, burn and feed chamber out of heavy stainless steel.  It was expensive, but since we were planning to concrete the whole system into place, we didn’t want to risk it ever burning out, and the temperatures get very hot.  We made ours 6 inch (150mm) diameter.  We debated it.  Lewie was barracking for 5 inch (125mm).  I couldn’t conceive of a smaller pipe taking enough wood to heat a bathtub of water, but in retrospect he may have been right. If anyone has tried smaller, let us know!

The plumber did a little design modification on his own, and made the burn chamber go horizontally for 6 inches then at a 45° angle, I think just because it made an easier and stronger weld.  In retrospect, I don’t know that it was a great idea. I would probably insist on it being horizontal if we were doing it again.

Our rocket chamber is 32 inches (81cm) tall.

Over the rocket chamber is a sleeve of galvanised 10 inch (25cm) pipe, and the gap between the sleeve and the rocket chamber is filled with rock wool.  In Version 1, it was filled with perlite.  We lit it up to try it out. It worked beautifully for a couple of baths then stopped working.  Giant frustration.  Took a while then we figured out that the perlite had all settled and compacted and wasn’t up to the job of insulation.  Vacuuming out the perlite to replace it with rock wool was interesting.

After the insulated rocket chamber the gases drop between the galvanised pipe and the bricks, and go out through a galvanised chimney pipe (the curved pipe on the left hand side in this picture).  At the bottom the pipe turns at 90°to the centre of the bath, then turns again and travels under the centre of the bath to come out at the head.  The bit under the bath is rectangular guttering stuck to the bottom of the bath.  Under the bath is filled with perlite and bricked in.  (We had a stack of old bricks put to good use on the project).

At the head of the bath, the chimney turns 90°again and goes up through the rock gabion wall (later filled with rocks).  It has a little cap on top, mostly just to look pretty, and above it the alsynite roof is shielded with a small sheet of metal.  A little smoke comes out when the fire is first lit, but after that not much comes out the chimney, not as heat or smoke.

Version 2, with rock wool insulation, worked beautifully most of the time.  And sometimes just refused.  For no good reason.

We never have totally figured out why. It’s one of those things where you make several changes and can’t tell which one worked, or if they all did.  But three modifications later, the system is working perfectly and perfectly reliably.  Mod 1:  we installed a small fan recycled from a computer in the chimney as a suction.  The idea came from some camping rocket stove designs we found that incorporated a fan. Mod 2:  We built a little semi-circular shovel to be able to remove ash from the burn chamber while the fire was going.  We found that ash in that chamber tended to reduce its area and choke the fire if you have it going for more than one long bath.  Mod 3:  We found a pudding basin that fits very neatly in the open end of the burn chamber – if you look at the first photo in this post you will see it.  We found that letting any air at all in that way made the fire more likely to burn up the sticks rather than horizontally as it is supposed to.

So, the final system.  We can fill the bath with warm water from the solar system, or cold water if it has been really cold and overcast.  With warm water, the bath is ready in half an hour.  With cold a little longer.  It probably doesn’t get hot enough directly under the bath to crack the enamel (as it would with the star bath) but I haven’t wanted to test that.  We fill it first and have a boogie board we put in the bath while it is warming so as to insulate it.

There is a big urn  lives beside the stove with sticks for the fire. We use eucalypt sticks about one to two inch diameter (25 to 50 mm).  Light a small fire in the bottom of the feed chamber, stand four or five sticks in it, and the flame burns horizontally through the burn chamber and roars up the rocket chamber.  The top of the rocket chamber has a big pot with a tap.  This gets very hot and can be added to get the bath to toasty, and refilled from the tap above it.

The hot gases flow along the chimney under the bath keeping it warm.  The sticks drop into the fire as they burn.  If you intend staying in more than half an hour or so, a bath wallah to add more sticks is very helpful. And to bring more wine.

This is a brilliant little video of an experiment done by Harvard Medical School.  It takes under two minutes, and you will never buy any of those household antibacterial wipes or handwash or floor wipes ever again.

The US Food and Drug Administration has recently banned them, both because they just lead to antibiotic resistance, and because several active ingredients are known hormone disrupters.

Bad for you.  Bad for your budget. Bad for people fighting antibiotic resistant infections. Bad for fish and all the other creatures – ones we eat and ones we don’t- trying to maintain some kind of fertility in an increasingly hostile world.  Ordinary soap and water, or for surfaces cleaning vinegar (bottom shelf in the detergent section of the supermarket), with, if you like, lemon skins in it for a dash of nice smelling lemon oil is all you need.  The rest is advertising hype.

So, this one is for you Angus, and for the others who have asked for more detail about building the bathroom “Worth the 30 Years’ Wait”.

Like everything permaculture, the first step is to “Observe and Interact“. We didn’t do that.

Our house has a beguiling view to the south, down a valley and off into the distance.  Some mornings, with mist hanging in the valley, it is magnificent. It seduced me into forgetting everything I knew about solar energy and aspect. So we built our main verandah facing south with the kitchen leading onto it, the kitchen roof sloping south, and the wood stove in the kitchen, and … can you see where this is going? In our hemisphere, a solar hot water system has to go on a north facing roof to work effectively.  To be wood stove boosted, the wood stove needs to be pretty directly under it, but our wet-back wood stove was on the other side. The design was all wrong.  You can’t shift the sun.

So we made do with a shower with solar heated water, that wasted too much water waiting for the hot to get through and that often didn’t get properly hot in winter, and a “star bath” – a cast iron bathtub out in the open with a fireplace directly under it. The star bath was glorious.  The fire kept it hot for as long as you like and lying back in a hot bath on a cold winter night watching the stars is one of those major life luxuries.  But lighting the bath was chore too far for midweek workdays and much too far for cold, wet, early dark midwinter midweek workdays.  When I mentioned “stubborn” in the original article, this was the source.  Getting the bathroom right meant going back to fix some fundamental design basics.

It took some years but eventually we reconciled to shifting the kitchen.  The north-east facing verandah doesn’t have the view but it is much nicer to sit on.  The wet-back slow combustion stove now sits directly under the hot water solar panels and tank, and the kitchen sink and the  laundry are a short run.  And it meant we could get hot water to the spot on the north-west side of the house that I had always wanted as the bathroom.

So step one is the one I think we all neglect way way too often, and that is to appreciate the utter intractability of physics. Site a house facing the view – or the street – and you will be stuck forever dealing with too hot, too cold, too dark, too much water wasted, too much power wasted, every element that uses heat or light a struggle. Get the aspect right and everything involving heat and light just flows.

When I say “we” for the rest of this post, I really mean my partner Lewie.  He did all the work on this building project and gets all the credit.

Step two was a bobcat to dig a trench along the uphill (north) side to take the drainage pipe, and also  a length of ag pipe to take storm water runoff away. Drainage pipes for the bath, shower, and basin were laid and the trenches backfilled.

Step three was to concrete in steel corner posts to take the roof and some extra steel posts to help stabilize the gabion walls.

Step four was to build a post and beam roof covered in alsynite.

Step five: install the shower tray and the floor.  The floor is diamond grid – recycled plastic interlocking grid – filled with smooth pebbles.  We’ve since started using diamond grid for paths and drives too – it’s an excellent environmentally friendly material for stopping wet, trafficked areas getting boggy. It has worked brilliantly in the bathroom  No shower mat needed.

Step six was to install the bath and its rocket stove.  The bathroom now has reliable hot hot water year round, from the solar panels in summer and the wet-back slow combustion stove in winter.  The only time this system fails is if it is cold and overcast and we have been away for a few days and the stove hasn’t been lit.  But the star bath spoiled us – I wanted to keep that experience.  I’m going to write a whole nuther post on its own about the rocket stove construction, because we found that there is not a great deal of information on the internet about using rocket stove technology this way, and there was a great deal of learning done along the way. The short story is that it allows us to fill a bath with lukewarm water, light the stove with a small bundle of eucalypt sticks (kept in a big pot next to it for that purpose), and an hour later have a hot bath.  The chimney goes all the way under the bath keeping it warm for as long as you are prepared to add a few sticks every half hour, and we still have the view of the stars albeit not directly above.

Step seven:  The gabion walls for the three outside walls (the forth wall is the door to the house) and the shower cubicle. We used 1.8 metre galvanised grid wire with a 50mm by 75mm grid.  Two parallel runs about 30cm apart, around the outside of the steel posts and back around the inside, tied across every metre or so with heavy galvanised wire to stop it bulging, then filled with river rocks.  We bought the rocks from a landscape supplier (along with the pebbles for the floor) and bucketed them into the gabions – slightly heavy work but the area is not too large and it only took a few hours to do.

The walls are filled to head height around the shower and two walls, but lower in front of the bath to allow a view over the garden and to the stars.  It works for us because we have no neighbours on that side and the bath is designed for use of an evening when no-one is out and about in the garden.

Step nine: plumbing:  We used retro style plumbing fittings, mostly recycled, and got a plumber in to connect the system to the hot water storage tank, which now sits on the roof directly above where I am standing to take this photo.  It means it is a nice short run and I can use the small amount of water it takes before it runs hot to water the plants. The out plumbing goes to another bathtub down the hill a bit, filled with gravel and reeds to filter it, then onto a clump of banana palms.

Step ten: Art deco light fittings found at the dump shop, refitted for 12 volt, and towel hooks on the forth wall.

Step eleven: plants.  I have very tall native ginger and banana palms around the outside on two sides.  The ginger is flowering now, hanging great heavy flower heads into the bathroom.  It is dense enough to be an effective privacy and breeze screen.   There are a couple of big pots with figs, hanging baskets of orchids and ferns hang from the roof around the edge, and I’ve planted around the edge at floor level with lilies, palms, and bromeliads, and crow’s nest and maidenhair ferns around the edge of the shower tray.   A jasmine and a honeysuckle vine both climb the outside of the wire and make their way through the rocks occasionally.

And finally, decoration.  One of the (many) nice things about rock walls is no fire danger, so there are candle holders poked into the rock walls, and I’ve started adding shells and sea glass and crystals and pretty rocks when I find them.  My two-year-old grandson, Teo, helps me find shells, and made a decision on his own to add some treasures to Grandma’s bathroom decorations.

I so love having fresh flowers in my bathroom these days. My bathroom “Worth the 30 Years’ Wait” has hanging baskets all around the edge, lilies along the side, and I’ve discovered orchids.   This orchid is right next to the shower-   I can admire it while I soap myself.  It is the forth orchid to flower this year, and so far my favourite with its delicate mauve centres.

I’ve never been huge on growing flowers before.  A nice fertile bit of soil and a choice of what to plant in it and an edible has nearly always won out.  I do like the beauty of many flowering edibles – they feed my native bees, attract predatory insects, and yield seeds for next year’s planting.  Right now I have mustard with bright yellow flowers – great for salads and going to be brown mustard seeds for sprouting and for curries and for pickles.  I have the waxy white flowers of kailan, or swatow broccoli, again wonderful in salads.  I have the purple flowers of endive, going to be seed for next year but mostly just because. I have dill flowering with yellow umbrella heads, good for salads and seed as a spice, and for attracting predatory hoverflies, lacewings, wasps and ladybeetles.  I have Queen Anne’s lace planted for the same purposes.  Soon there will be the lovely little blue flowers of Nigella that I grow for its peppery seeds for pickles and curries.  I would have nasturtiums for salads too but the wallabies found a hole in the fence again and they love nasturtiums even more than I do.

But flowers grown just for themselves are a rare thing for me and I’m discovering a whole new indulgence.

This river lily is growing under the towel hooks. Back when my mother was a girl, orchids and lilies in corsages were a gift for a special date.  It feels very luxuriant to have them all the time.

For about 9 months of the year we have silver beet, (or Swiss chard if you are in US).  There’s a few months from midsummer to midautumn when the grasshoppers feast on any left in the garden, but there aren’t many left because most spring plantings just bolt to seed.  Egyptian spinach – Mulaheyah – fills the gap.  But proper English spinach, now that’s another thing.

Spinach is up there with kale, one of those superfoods with enough vitamins and minerals and phytonutrients to make vitamin pills look silly. In particular, cooked spinach is a stunning source of Vitamin K, useful for preventing osteoporosis among other things.  Silver beet substitutes for spinach in most recipes, but real spinach, soil grown in season, is a treat. I’m at the edge of the climate range for real English spinach, but for a month or so each year in late winter we feast on it.

Silver beet is a bit tougher and does better for longer cooking.  Spinach though just needs to be blanched.  Under a poached egg, with lemony garlicky mushrooms, in Greens as Themselves.  Or in these little spinach and cheese rolls that are not baked but shallow fried so they come together fast.

The Recipe:

This makes just a dozen little canape sized rolls. I like making recipes in small quantities myself – it saves leftovers and often there’s a quantum leap in how fast and easy it is to make a little batch to a big batch.  And for you, a small batch gives you a chance to decide if you like it or if you want to tweak the recipe for your own taste before you commit too many ingredients.  But, having said all that, the recipe can easily be doubled or trebled, and I would think they would freeze well before frying –  just like ravioli, in layers separated with greaseproof paper.  Which would allow you to just take a few out to fry for lunch boxes whenever. I am looking forward to trying them out on nearly 3-year-old Teo but I imagine they might be very kids lunch box acceptable.  They are very adult lunch box acceptable.

To make the wrappers:

Blend an egg with ½ cup of plain flour (wholemeal or unbleached) and a pinch of salt to make a kneadable dough.  If it is too dry, add a teaspoon or two of oil.  This is a basic pasta or won-ton recipe, so I would think you could use bought wrappers if you like, but making your own is so very easy and you get to use real egg.

Let it rest for a minute while you make the filling, then roll the dough out with a rolling pin on a well floured benchtop, or with a pasta machine, to make a long strip, about 10 cm (4 inches) wide.  Make the ends as square as you can so you don’t have to trim too much off to square them up.

Meanwhile, make the filling:

Blanch a bunch of spinach in boiling water for just a minute or two to wilt it, then drain and squeeze it to remove all the liquid.  It will reduce to about ¼ cup.

Put it in the food processor (you don’t need to wash it after the pastry blending) with

• 1 ball of bocconcini (or you could substitute 35 gm or so of mozzarella or any really melty cheese)
• 1 slice parmesan or any tasty cheese

Pulse the spinach in the food processor with the cheeses very briefly, just to chop it all together without blending it. Taste the filling and add salt to taste.   I like adding half a teaspoon of grated lemon rind too.  Or, for adults, a little touch of wasabi. Taste and see what you think.

To assemble and cook:

Mix a dessertspoon of plain flour with a little water to make a paste.  Use a pastry brush, or just your fingers, to spread it thinly over the pastry.  Leave a smidgen for later.

Lay the spinach mixture down the middle, then roll it into a log.

Paint the top side with the leftover flour and water paste and sprinkle with sesame seeds.

Cut into 75 cm (3 inch) lengths, then let them sit to dry on a floured benchtop for 10 minutes or so.

Heat 10 cm (½ inch) or so of oil in a heavy bottomed fry pan.  (I use light olive oil for frying like this because it has a high enough smoke point and it’s monounsaturated). Fry the rolls until they are golden, turning with tongs.

They are wonderful warm but also ideal for lunch boxes or made-ahead hors d’oeuvres with a spicy dipping sauce.

Some years I don’t bother with European cabbage.  My winters are short.  The cabbage moths are active right into autumn, and back by mid-Spring. Cabbages take up a surprising amount of room.  You harvest them once (unlike broccoli or silver beet) and then they’re gone.  Chinese cabbages are easier and fill the same slot, sort of.

And then I have a cabbage year and remember why I love them and vow I will plant cabbages every year.

We’ve been eating pink coleslaw, with homemade mayonnaise, shredded cabbage, grated carrots and beetroot and finely diced red onion.  We’ve been eating shredded cabbage sautèed very quickly in half butter, half olive oil till it gets little crispy brown bits. We’ve been eating mini vego Chico Rolls.  We’ve been eating minestrone. We’ve been eating Okonomiyaki – Japanese cabbage pancakes.  We’ve been eating soft boiled eggs chopped up in a bowl with diced cabbage and a little mayo for breakfast.  I’m even thinking I might make sauerkraut this year.

Remind me next autumn that cabbages are so worth it.

So here it is, almost a week past Imbolc and I still haven’t Imbolc’d.

Imbolc is an old Gaelic word, there in the earliest of writings. It means “in the belly” and it is easy to see why this turning point in the old Celtic and Gaelic calendars was named for it.  It marks the midpoint between the winter solstice and the spring equinox.  Since the winter solstice the days have been getting longer, but so slowly and by such a tiny amount that you are forgiven if you haven’t noticed.  From now on though the exponential growth part of the curve kicks in.  It’s almost like watching a 15 year old boy grow.  If you look at it on a graph, it’s the spot half way between solstice and equinox where the long flattish part of the curve turns into a steep slope. It’s such an easily noticed change that pretty well every culture in the world has some kind of festival marking it – Groundhog Day, St Brigid’s Day, Candlemas, Setsubun, Vasanta, Tu BiShvat. And  in the eightfold year calendar, Southern hemisphere variety, it’s Imbolc.

I find this calendar really useful as a gardener.  The seasons creep up on you.  Today I have the wood fire going as we pass through a cold snap on the heels of the east coast low.  But in the leafy planting break coming up, I shall plant basil and molokhia and resist the temptation to whack the last of the cabbage seeds in anyhow.  Planted now, they would just bolt to seed if the cabbage moths didn’t get them first, because cold as it might feel, Spring is just about here.

But I like it better than that even.  It gives me a gentle nag to make time for those things that are important but not urgent, the things that get pushed aside in the busy-ness of life. So Ostara (the Spring equinox) with its rash of eggs and flowers and lambs and calves makes thinking about children and hope and future really obvious.  Beltane maypoles are hot and sweaty and great for remembering how good it is to have a fit and strong and healthy body.  Shakespeare’s “A Midsummer Night’s Dream” is set on the midsummer solstice. Lammas at the end of January celebrates achievement. Mabon on the autumn equinox brings in the harvest with gratitude. Halloween remembers the ancestors and Yule reminds us that in hard times there is always friends and family and community.

Imbolc is about the still not obvious beginnings of things.  At Imbolc each year I try to take a few days out to reflect on: What is there, waiting to be born, in my life?  What am I nurturing, anticipating, brooding?  As the first of the chooks start going clucky, I wonder, what are the eggs I’m sitting on this year?

This year, with the vocational education system in a right old mess, my “other job” has fallen out from under me. I can’t say I’m happy about it but I have a Pollyanna streak in me, and it has freed up time.  I could take on a new major project.  I could, I just about could, do something big and new. Maybe I should.  Should I?

The green doesn’t look real does it?  But it is, late winter in my garden and skies that look too blue to be real and garden greens that look too green to be real.

There was a lean patch there for a bit, where I didn’t reap what I didn’t sow a few months ago.  But it’s back. This is such a productive time in my part of the world.  Spring here is often harsh – windy and dry and unexpectedly hot.  It means seedlings need shadehouse raising and coddling, and I am always a bit stingy with watering as I wait to see what the fire season will bring.  Summers lull you into a false sense of great expectations, with rainstorms often enough to keep things going so long as they are well established and there is plenty of mulch, but then comes a frizzle day – a single day with temperatures in the 40’s and a hot dry north-westerly wind and you can’t stay home all day to rig up shade and mist and it’s all gone in one fell swoop.  Then the late summer-early autumn floods when you find out if your drainage really is good enough.

And then comes this, late winter in my frost-free garden, with a season of just-enough rain and lots of clear, bright winter days and bandicoots kept (mostly) out of the garden beds and wallabies kept (mostly) out of the perimeter fence and bush turkeys kept (mostly) from doing too much damage and I think the resident possum has met up with the resident carpet snake so we are between possums.

Spinach is the glut crop.  Real spinach grown in the ground in season is a different thing to the little packets of hydroponic baby spinach you get in the supermarket, and now is about the only time of year you will find it at farmer’s markets and in gardens.  Spinach  triangles and gozlemes and frittata and gnocchi and pie and piroshki and polenta and pikelets and pakora  and soup and saag (both with and without meat) and under a poached egg or mushrooms for breakfast most mornings.  And today little spinach and bocconcini rolls that I’ll post a recipe for sometime soon.

Lettuce is the other glut crop, with some kind of winter salad most days. There’s any amount of the leafy annual herbs – rocket and parsley and coriander and dill and  spring onions too.

We’ve started harvesting asparagus, too early but there you go.   Broccoli and snow peas and cauliflower  and  celery are coming on nicely, and carrots and leeks and and beets. My  broad beans are flowering. It’s really too warm for them here but I have hope of at least a little crop.  I have a nice stash of macadamias, hopefully enough to last through till the pecan season in autumn. The last of the limes to go with avocados.  The last of the  mandarins to last through till the strawberries (now flowering) start. 

A late winter garden in sub-tropical climate is a lovely thing!