Generating Steam in a Wood-Fired Oven

A question of steam…

On artisan bread baking forums, you hear time and time again that one of the keys to baking great crusty bread is steam.  Another key is of course a lot of heat.  So while the wood oven gives you the heat, how do you get the steam?  And why would you want it?

Firstly, there are the caramelization and Maillard reactions, which will cause the desirable browning of the outside of your loaves.  Unless the surface sugars of the dough are in solution (dissolved), caramelization may be more like incineration. Secondly, without steam, you will get a thick and dry crust, which is less desirable than the crackly and thin crust you can achieve with steam.  Thirdly, steam around the outside of the loaves will delay the hardening of the crust allowing the loaves to expand more in their first few moments on the hearth.

In fact, this early growth process is caused by steam generated inside the dough for three reasons – but especially the heat of the hearth converting dough moisture to steam at the surface at which the dough meets the hearth (the bottom of the loaf) . However, in a (nearly) sealed unit like a wood-oven with the door plugging the entrance, if you are baking a few loaves at once the dough will release a lot of moisture which will contribute a steamy atmosphere – so once baking is underway, you are going to have self-generated steam.  So the crux of the matter is getting moisture in the right places (i) before the loaves go in, and (ii) during the first few minutes as the crust forms.

I wet the surface of my loaves liberally with a £3 garden centre hand-pumped spray gun (right hand side), and once the loaves are in the oven the professionals use a hand-pumped pressure-spray like the one on the left.  Also available from a garden centre.

So while professional bakeries might sometimes use steam injection rack ovens which cost many thousands of pounds, you can get a great result using cheap tools from the garden centre.  I have another method using a £5 pack of lava rock in a steel baking tray.

Once the fire has been removed, I put my tray of lava rock in the oven to heat up as the oven temperature evens out, carefully depositing around 200mL of hot water onto the rocks while wearing a glove, at arms length.  I load the oven with my loaves at this point.

You can see the steam rising in this example.  Remember that very hot steam is mostly an invisible gas, and that steam is dangerous and can cause burns. This is especially important if you are opening the door to a steam filled oven. Moving forward I’ll be using a pressure sprayer to wet the lava rock, removing the danger another yard from myself…

I’m currently avoiding pressure spraying the hot brick surface directly in case I cause damage to it, though that may be overkill as a 300ºC surface will probably turn it straight to steam.


Photograph: Generating steam in a wood-fired oven using lava rock

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On the Nature of Pre-ferments

One of the toughest things I’ve had to figure out when learning to bake is what should pre-ferments actually look like when they’re ready to use.  This goes for both the poolish or biga type ferments which are called for with certain French or Italian breads and pizza, but also for sourdough.  So I thought it might be helpful to take a few pictures for your interest, reference and constructive criticism.

Firstly, let’s think about poolish vs. biga.  Poolish is a wet pre-ferment, containing the same weight water and flour (ie. 100% hydration in bakers’ terms), it contains less yeast than a dough and should be left 12-16 hours to ferment prior to use.  Biga is a drier pre-ferment (70% hydration, ie. 70g water to 100g flour), which is in some ways a fermented dough.  As it is going to be left for some time, and the yeast will be slightly held back by the dryness.  For a day-before-bake pre-ferment, I use degassed tap water adjusted to 24ºC using boiling water from a kettle.  There is no salt in my pre-ferments.   I degass British tap water by leaving it overnight with a loose lid, so the chlorine can escape.

Just like a dough, your pre-ferment will grow.  Don’t forget to use a container bigger than your need (eg. 4-fold larger)


A couple of days ago, I made a large poolish to prepare Pain Rustique for the local homeless shelter.

Example Poolish:

In this example poolish, I fermented 6.5kg of Shipton Mill strong white flour with  6.5kg of water, and 1tsp of Doves Farm quick yeast.  I actually mixed it together in a spiral mixer for about 1 minute and medium speed, and left it to ferment for 16 hours in a plastic beer container.  You can see from the “time lapse” photography, the poolish grew by about one quarter in the first 6 hours, and by the morning, had nearly doubled in volume. Stiffer pre-ferments will hold their structure better and can increase in volume several-fold.

Quite a few things are going on in a poolish, but among other things the flour particles are getting fully hydrated, the yeast is producing a lot of flavour, gas is being produced, and the fermentation develops the gluten.

But – how do you know it is “working”?  You will take the lid off your container, and it will almost be alive with movement.  Bubbles will be reaching the surface, and it will not be still.  If you give the poolish a stiff knock – quite a few bubbles will appear.  I’ve taken a photograph of a poolish this morning as a reference.

Example poolish surface:


Rye Sourdough Mother

Now let’s take a look at a rye sourdough mother, of the sort you might use in Pain au Levain or 100% Rye bread.

Example Rye Sourdough Mother:

In this example, I’ve refreshed a rye sourdough mother.  I’ve taken about 10g of a rye mother from the fridge, and added it to about 100g organic rye (Cann Mills), and 100g degassed water.  I leave it on the counter overnight (17-19ºC) in this neat Sisteam plastic pot.  I’m mixing it up using a silicone spatula, in a polypropylene bowl, all of which makes cleaning up really easy.  You can see the air bubbles which have formed.  The mixture is really stiff, and doesn’t flow (over a minute).

Stiff Rye Sourdough Mother:


This close-up shows my rye sourdough mother not flowing.  Interestingly, a more liquid rye starter will favour certain fermenting beasties over others – and can lead to a fall off in the number of Lactobacillus sanfranciscensis which I tend to think of as a sourdough bakers replacement for Saccharomyces cerevisiae.  In my hands, a flowing rye sourdough mother leads to loaves which don’t hold their shape – that also flow outward, probably due to overpopulation of the ferment with bugs that digest gluten.

Liquid Levain

This is an example of a liquid levain, straight out of my fridge.  You can see that it flows.  This was seeded from my stiff rye mother, and its about 130% hydration strong white flour.  This is a liquid culture of yeast (funghi!) and bacteria, which will be a very different population to the stiff levain above.  My favourite Pain au Levain recipe utilizes both stiff rye mother and liquid levain mother, hence, maintaining the two cultures allows a more diverse set of microbes to ferment your bread.  At a later date, I’m going to blog on the diversity of microflora in sourdough mothers, taking academic publications and reviewing them in plain(ish) English.


Waste and Want

On a domestic level, it may feel plain wrong throwing out spare sourdough culture, or the end of an unused poolish.  If you happen to be making pancakes, throw in some spare sourdough – it adds character.  If you are making a yeasted bread, consider doing the same. I find my poolish keeps fine in the fridge for a week, and on the counter fermented dough in a sealed box is fine for several days.  Likewise, you can easily reduce the volume of rye sourdough you keep to a minimum (eg. 100g) which also reduces waste.

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Handmade and homemade: how to do pizza dough bases from scratch

Twenty years ago, I used to buy Napolina pre-cast pizza bases from the supermarket.  I’ve checked and strangely they still exist.  Now if you want to eat glyceryl monostearate, glyceryl distearate (E471), if you want to consume palm oil and glucose, and if you couldn’t care less how your food tasted – go ahead, at 85p per base is cheap.  However, I don’t consider mono and diglycerides of fatty acids to be “food”, glucose has no place in a bread product, and as for palm oil – isn’t that “the hidden ingredient causing ecological disaster“?  Besides oil is not an ingredient in pizza dough, not according to my foodie dogmatism in any case.


The poolish prior to overnight fermentation

There are plenty of guides as to how to make pizza, I published some tips and tricks last year in my post September pizza from my wood-fired oven – the tricks I’ve learned by trial and error.  I’ll assume you’ve read that if you are reading this, if you haven’t – consider reading that post first!  I’m going to include links to various bits of equipment, but you can substitute anything I recommend with what you already have at home.

But cooking is very much a visual activity, so I’m going to include a few pictures about what things should look like along the way, visual tips so to speak. First off is the poolish.  If you want to make pizza dough that stretches without ripping, and a cornichione (crust) that puffs up nicely with a membrane-like skin that caramelises and chars deliciously, dough needs time.  This doesn’t cost you any time net, but it takes planning.  I make my poolish 48-72 hours in advance.  The poolish will be a mixture of 00 flour and water in equal weights (eg. 200g of each), the water will have been left to stand and “de-gas” with a loose covering for a few hours and will be 24ºC.  You can adjust the water temperature with a dash of boiling water.  If the water is too cold, the yeast’s fermentation will get off to a poor start, which will have downstream consequences, if the water is too hot, you can kill your yeast. I invested £10 in a digital catering thermometer which works just fine.  Good for yoghurt making too!  You are going to mix the flour and water quickly in a mixing bowl with a wooden spoon, I prefer something like an Araven Polypropylene Mixing Bowl which seems to help insulate my concoctions in my cool kitchen. Once all the flour is mixed in and wet, and there are no big lumps, add a sprinkle of yeast. I use about one quarter teaspoon of Doves Farm Quick Yeast, which is probably one quarter gram. Yes, this is the least scientific thing you’ll see on this blog, and apologies. This yeast doesn’t require any activation step, and there is no need to add sugar. Now mix in your yeast, and cover the bowl with clingfilm and leave it overnight on the kitchen counter.  Ideally, this environment should be above 16ºC.  You can also fridge this ripe poolish for 24-48 hours prior to use.


Dough balls prior to rising

The next morning you will make the 55% hydration dough, taking into account the weights of water and flour already present in your poolish.  You can let your dough develop for 3-6 hours at room temperature, then form (220g) dough balls which can be let ripen for 2-6 hours.  My experience is that dough balls which have been let ripen for a longer period are easier to work with to generate a really thin pizza base that doesn’t rip.  You can also fridge the developed dough balls and use them in the following days, though the quality of the end product will diminish over time. Use olive oil to prevent them sticking, I like to lightly coast them in olive oil using my hands prior to rising.  I use a cheap plastic BPA-free box for the rise, of the kind you can get in a pound shop,  and keep the lid on tight to stop a dry crust forming on the dough balls.


Risen dough balls

If you are in an almighty rush you can use the dough balls within an hour, but that is somewhat of a wasted effort. I’ve included a picture of the risen dough balls so you know just how big they get.  The thin sheen of olive oil is helping to prevent them sticking together.  The alternative is stackable pizza dough proofing boxes, which are just a bit big for a domestic kitchen.

In previous posts, I’ve talked about my enhanced pizza sauce, which has been evolving.  Get some tinned  San Marzano tomatoes, and fish just the tomatoes out of the tin with a fork.  I no longer use the juice in my sauce because the product is too watery, and requires heating to cook off the excess moisture, or you end up with a watery pizza. Yuck! Use the tomato juice for something else.  When you mash your tomato fruit, you’ve got the pizza sauce, no heating required.  I sometimes add garlic oil made by lightly frying very thinly sliced garlic, filtering out the garlic with a tea strainer.  The photographs below gives you an idea of what colour the garlic should be, and illustrate the separation of the tomatoes.

Some unfinished business for me is weighing exactly how much tomato sauce to put on each pizza.  But we’re talking between about between a one and two ounce ladle, which is 30-60 grammes in metric.  I use the underside of the ladle to gently spread the sauce out, in a circular spiral movement from the centre of the pizza outwards.

A nice touch with fresh mozzarella balls is to drain the mozzarella really early on, and wrap it in four or five layers of kitchen roll.  As it warms up in your kitchen, it will give up more moisture than straight from the fridge.  If I’ve more time, I shred it into 15-20 pieces by hand, and dry it between layers of kitchen roll.  Again, we are limiting the addition of moisture.  I don’t rate supermarket pre-shredded mozzarella, which is supplied very dry, even if you sometimes see a similar product being used in pizzeria videos on YouTube.  You gotta wonder what effect the anti-caking agent (eg. potato starch) will have on your pizza, including flavour effects as the cheese caramelizes.

In terms of cooking, you can either cook your pizza full blast in a domestic oven – yes 260ºC is just fine, or if you have one cook it in a wood-fired brick oven for best results at 310ºC – 500ºC.  For best results use a baking stone which needn’t cost more than £10. The function of the stone is to simulate the pizza oven hearth, which stores so much heat that it can cause a steam burst, which gives you “oven spring”.  The water in the dough gets turned into steam in the first few moments of contact with the cooking surface, causing the dough, and therefore the cornichione to expand rapidly.  The electric pizza ovens in most pizza shops and even artesan pizzerias seem to be set at 310ºC, but  you do get far better results above 450ºC in my opinion.

So let’s take a look at a finished product cooking in my wood-fired oven:


Then also worthwhile looking at a finished product:


Happy pizza baking!

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Heating the Mug – The science of achieving the right temperature in mug-brewed tea

Tea-making behaviour has changed in the West, from loose leaf tea brewed in pre-heated pots, to “tea” bags brewed in mugs.  But in this movement to convenience, has the flavour been lost in methodology?

From adverts for brand tea bags to instructive videos on YouTube, self-styled exemplars fail to recognize the essential loss of consistency in the transition between the pre-heated pot to the mug.

Brewing tea is not nothing more than the addition of once boiling water to a location near the tea.  Mass marketing suggesting this method might be adequate contributes to an experience of modern life that is rubbish, meaningless and unsatisfactory – with an £84bn transnational encouraging human beings to irrationally follow a half-wit knitted monkey ted.   “Knat’s piss”, I hear my long-gone grandma call from her dining room table in 1985, deriding the product of a near miss between tea and nearly hot water in her broad Lancashire accent. Do not follow the monkey, though because others do, Unilever’s shares have risen about 4-fold over 15 years.

You must plan to enjoy your tea, and plan to spend the time and effort on making and savouring a good cuppa is a revolutionary act!

Making tea in a china mug is also a scientific endeavour. If you spend 40 minutes drinking tea each day, not uncommon here in the UK – you may spend 3 years of your life engaged in this pursuit. If your method of brewing the cuppa is lacking, this might mean you end up sipping an unsatisfactory beverage for 1000 days of your existence. It might seem like a sentence: but it need not be, and this brief article might just be your get out of jail free card.

Lamenting the lack of flavour in the cups of tea I was drinking at home, compared to at some cafés, I did an experiment with my digital catering thermometer.  A tenner ensures the 3 years of my life spent drinking tea will be more than satisfactory, but a pleasure.

According to Lifehacker, black tea should be steeped at 90.5 – 96ºC. Though the water in your electric kettle may be close to 100ºC at peak, it cools rapidly, and the temperature drops of significantly when poured into a much cooler receptacle like a cup or a mug. The colder and heavier the mug, the larger the thermal mass which will suck the energy from your boiling water, potentially leaving your tea brewing water tepid.  But just how much does the water cool, and will it affect the quality of your cuppa?

The first part of my experiment simulated what happens when I made a cup of tea by simply pouring freshly boiled water onto a tea bag in a cupboard cooled mug, but without the bag: the water was rapidly cooled by the colder mug to 83.5ºC, and fell quickly. However, after allowing the mug to equilibrate with the “boiling” water for 30 seconds, then discarding the hot water, and replacing with another mug full of freshly boiled water – I achieved a temperature of 93ºC. Within 60 seconds, and certainly at 120 seconds, this produces a much more satisfactory cup of tea than tea made in a cupboard-cold mug.  Try it for yourself.

Therefore the remedy for a post-“heated-pot teapot” world is “heating the cup”.  Let this be your manifesto for the moment. Dispense with revolting half-brew. And tea-up for the revolution!

NB. If you are a heretic, and you add the milk to your mug first, an acceptable variation is to microwave the tea bag in the milk for 20 seconds prior to adding the boiling water.  This is a rapid route to “builders” tea, which in addition facilitates the extraction of certain fat soluble flavour compounds from the tea.

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Where can you buy San Marzano Tomatoes in the UK? – Autumn 2015 update

A few readers have pointed out that the most common stockists of canned San Marzano tomatoes in the UK are nearly all marked out of stock.  I believe this is a seasonal issue, and will change over the coming weeks.  But I’m sorry to say – this does look like a drought.

However – if you look hard you can still get them – if you buy bulk or bigger cans. I suspect the most cost-effective outlets will have stock within 2 weeks.

You can buy 24 tins of San Marzanos for £45 from NifeIsLife, or 2.55kg catering tins from Mediterranean Direct (£9). Finally, you can buy double size tins (800g) of Strianese brand San Marzano tomatoes from Lina Stores for £1.75 + delivery.  However they only have 4 cans left in stock as of today.  Wow.

But you should also consider low stock turnover sources, such as your local Italian deli – they may well not run out of stock during late Autumn.  Finally, ask your deli how suitable their tomatoes are for making pizza sauce.  I find the top quality Italian deli tomatoes to be pretty good, even if they are no substitute for the excellence of San Marzano DOP.

News Update: 12th December 2015: Just in time for Christmas, Lupa Foods have both their 12 cases of 400g tins, and single 400g cans of San Marzano tomatoes back in stock! And once again you can also get the 12 x 400g tin case from Amazon. Though Vorrei and others are still; out of stock.


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The Dome Gauge (also known as “the indespensable tool”) – Building my First Wood-Fired Oven

There’s a lot written about building a wood-fired brick oven, but possibly the most psychologically difficult barrier to beginning once you’ve built a base – for most of us who haven’t laid a brick before – is the assembly of the 3-dimensional arch which is the dome.

Once you’ve sketched it out, you probably realise the second biggest challenge will be working out how the opening arch (through which the food will pass) meets the dome, and finally – if you do include a chimney in your design, how on Earth you build that on top of your structure without weakening the dome or opening arch – given that there is going to have to be a hole for the smoke to pass through. The number of collapsed chimney arches I discovered in my online research reminded me that enthusiasm and drive will not overcome physics.

If you were building a wall, you’d use a spirit level, but if you are building a hemispheric dome (bread oven), or flattened hemisphere (pizza oven, Naples-style), you need something else to help guide how far each brick must lean inward, in successive layers of brick.

A dome gauge (indispensible tool)

My Dome Gauge

Part of the solution will be creating a dome gauge, which I’ve never seen for sale commercially.  I looked at a lot of online forums, and came up with my own design utilizing things I could get from hardware and DIY stores.  In particular 6mm screw thread rod was integral to the design, inserted through a rotating trolley wheel in which I’d drilled a 7mm hole – secured with wood resin. The dome gauge is held in place in a wooden frame on your brick hearth, the frame being a rigid straight-edged figure of 8 affair, jammed inside the first brick layer.

I used a handful of 6mm steel components, and these have definite names in the trade, the rod being “Steel M6 Threaded Rod” (£2.18 per metre from B&Q), I used two M6 Threaded bars, and a variety of M6 bolts, nuts and washers. It may be worth considering using a serrated flange nut, because the frequent manipulation of the dome guage can cause your nuts to loosen. The right-angle is called an “angle bracket” or corner brace, and this is what will make contact with your half-bricks in your build.  If you are building for a potentially commercial operation baking bread, or community bakery, you might want to build using full bricks, but this is not necessary at all for domestic baking or pizza.

You can also see this dome gauge in use in the photograph below as I added the third layer of dome bricks.  Note: the hearth is protected from the fire mortar with plywood, and no holes have been drilled in the hearth bricks.

The Dome Gauge Tool in Use

The Dome Gauge Tool in Use

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My first Pain Rustique with local flour from my wood-fired oven

I’d been looking for a simple bread to hone my bulk bread making abilities, and as I was leafing through an excellent book about wood-fired baking as a leaving pressie, I came across what looked like a simple candidate recipe for something called Pain Rustique in the excellent book “From the Wood-Fired Oven“.

Having had enough of variable results from whichever flour was available at the supermarket, I’ve taken once again to buying my bread flour from Wessex mill (see photo below).  I’ve been buying rather large

Wessex Mill - Good Flour with Known Provenance

Wessex Mill – Good Flour with Known Provenance

16kg bags of their Strong White Bread Flour picked up at the mill’s tiny front door shop. They do ship nationally.  However, looks like the biggest bags available online are 10kg (just £11), and they ship throughout the UK.  I rather like them, not only because I ate bread my own mother made with their flour when I was little, but because they publish a grist map showing where the wheat they mill comes from – but they also print it on the back of every bag.  This is local to me, so its a bit greener, but the flour is so good I’ve seen it for sale in West Wales.  I have also heart that Shipton Mill flour is very good, but that’s a lot further for the flour to travel, but with any flour bought from the mill – you are getting better flour for around one-third less than the supermarket – which means the baking is relatively economic.

The Pain Rustique formula I followed started with an overnight poolish of 800g strong white bread flour, 800g water (32°C), and one gram of instant active yeast. I mixed it all up mid-afternoon with a wooden spoon in a plastic bowl, cling filmed it, and left it on the worksurface overnight for 17 hours.  Now if you are turning into a mad baker, you need a mad baker’s mixing bowl so get yourself this catering grade 11 litre Araven polypropylene bowl and a small stack of smaller 6 or 7 litre bowls for smaller batches. They seem to be everything-proof, and don’t poison sourdoughs like steel bowls.

The next morning I added 300g more water (32°C), 800g more flour, and 3g of malt powder (dark malt flour from Wessex Mill).  I left my dough to autolyse for an hour then added 1 level teaspoon of instant active yeast (~5g) and 28g of fresh ground rock salt.  My favoured sea salt is Le Guerandais Coarse from Brittany, France – you might want to find out more about their cooperative. My favoured yeast is fresh, but I settled for Doves Farm Instant Yeast which seems to be easier to reseal, and

seems to stay fresh and viable much longer than other packets.  This dough got about 5 minutes at low speed (setting 1), using the steel spiral dough hook mentioned before.  I left the dough in its bowl, clingfilmed for about 90 minutes, giving it two folds every half an hour – try wiping groundnut oil around the rim of the bowl, it really helps get a good seal so your dough doesn’t crust and dry.

Finally, I floured a tea cloth up as a couche, tipped and spread the dough out a little, and cut it into four rustic shapes, each nested in couche – well floured, and proofed for 45 minutes, before transferring into my hot brick oven.  I lost about another 15 minutes clearing the last ashes, and didn’t allow the oven to cool down enough, and neglected to wipe the oven.  The plank you see in the picture is what I use to transfer the uncooked loaves the 100ft from the kitchen to the wood-oven, and back again, dusted with inexpensive NatCo coarse semolina.

Four Pains Rustique from the Wood-Fired Oven

Four Pains Rustique from the Wood-Fired Oven

I should have wiped down the floor of the oven with a wet clean traditional mop, one that won’t melt … keep one that you don’t use for anything else! I should have let the oven equalise and cool, but I didn’t.  Largely – this was due to (lack of) timing, and coordination – if I’m brutally honest!

So here are the results.

They look good – but as the oven floor was too hot, being well over 330°C.  The bread looks nice but the base was burnt in three of four cases.

Result: The Crumb

Result: The Crumb

I’ve also included a cross-section of one of the loaves below.  You can see the nice open crumb structure, upon which I place a lot of value.

Disappointed that I hadn’t achieved perfection, I began the entire process once again, immediately mixing up the poolish for the next day – but the loaves from the following day’s bake were too delicious to survive to camera – so I can’t show you what they looked like.  Happy baking!


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