Metric Bread





Introduction: Metric Bread

About: I make custom copper signs, metalwork and prototypes. I am one of the hosts of the "3d Printing Today Podcast", available on iTunes.

Once we wrap our minds around the metric system it makes everything easier including baking bread! You can't get too far into the world of bread baking before you run into the concept of a "Baker's Percentage". This important principle and a little hack involving the metric system combine to make the easiest way you have ever seen to make bread. It's not just a recipe, it's a master recipe, it's the only recipe you will ever need and once you learn it you will say to yourself "Damn, why does everyone make bread recipes so complicated?"

Step 1: Baker's Percentage

Baker's Percentage is an idea which comes to us from the big guys, commercial bakeries which need to be able to scale up a recipe to make a batch of dough big enough that you could hide a body in it. The idea is simple although the name is a little deceptive. A baker's percentage recipe expresses all the other ingredients as their percentage, by weight, of the flour. For instance a lean bread dough could be written as:

Flour 100%

Water 70%

Yeast 1%

Salt 2%

The astute reader will notice that this adds up to 173% but remember these are bakers, not mathematicians. We are really talking about proportions more than percentages but who wants to quibble as long as there is delicious bread. It's simple to use. You choose how much flour you want to use (whether you measure by the gram or the 40lb sack) and scale the rest of the ingredients to match.

Step 2: Percent Hydration

The most important ratio in a bread recipe is the ratio between flour and water. This determines much about the handling characteristics of the dough and the texture of the final product. In baker's lingo this called the percent hydration. It makes the difference between a 60% hydration bagel and an 80% hydration ciabatta. This is the biggest variable to tweak when experimenting with a recipe.

Step 3: Weighing In

A few years ago when I started baking a lot I bought a scale and started weighing my ingredients whenever possible. It is faster, easier and much more accurate. A kitchen scale is a common device in much of the world, but in the US it is virtually unknown outside commercial bakeries and the kitchens of dedicated home bakers. The logic is simple: It is difficult to accurately measure a flour by volume. The density of flour is too variable. A cup of light and fluffy flour has much less flour than a firmly packed cup. Now most of us have learned not to pack the flour in the measuring cup but there is still quite a bit of variation from one baker to the next. It is hard to know if your cup of flour is the same as the recipe author's cup of flour. If you are measuring out 6 cups of flour individually and there is a substantial error in each measurement this can add up to a large inaccuracy. Weighing things solves all that. You only make one measurement and it is much more accurate. Your kilogram of flour is the same as the author's kilogram of flour guaranteed. There can be small differences because of different moisture levels and different densities of different flours, but it is still much more accurate than volumetric measurement.

Step 4: Going Metric

That brings us to our trick: Simply start with a kilogram of flour. When the flour is 1000 grams the rest of the math is so simple that even a baker can do it in their head. If you want 68% hydration than means 680g of water. If you want to make super dense pretzels add 550g of water if you want a super holey ciabatta add 800g. It is simple to experiment. A kilogram of flour makes a batch of dough which makes 2 nice loaves or 4 good size pizzas or a dozen rolls or pretzels or bagels depending on how big each one is. It is a good size batch to work with and can easily be mixed and kneaded in the usual home size kitchen aid.

You might be tempted to measure out your water by volume and that will probably work well enough if you have an accurate metric measuring cup. Water weighs more or less one gram per milliliter, although this varies somewhat with temperature. But you have the scale out already so why not use it.

Step 5: Salty Talk

Unless you are from Florence Italy you will want some salt in your bread. The Florentines traditionally forgo salt in their bread because their seaside neighbors in Pisa once tried to gouge them on the price. The Florentines replied "Nyahh nyahh nyahh! We like our bread better without salt. So there. How do you like that." Then they sent gangs of drunken teenage boys to Pisa in the middle of the night to push over the tower and the rest is history. Well maybe not just like that, but the point is that bread is better with salt and you would have to be in pretty a pretty dire situation to want to leave it out. 2% is a pretty standard bakers percentage for salt which in our recipe translates to 20 grams. Most kitchen scales will measure this accurately enough but by luck this is also almost exactly a tablespoon if you are using regular iodized salt. If you use kosher salt it is a lot less dense so the weight measure is the same but if you measure by volume you will get significantly less saltiness. If you use Maldon fleur de sel I don't want to talk to you. You are probably so rich that you have someone to bake for you and don't need to worry about any of this anyway. I recommend measuring your salt separately then adding it, but if you want to trickle it slowly into the mixing bowl as you watch the scale slowly tick up 20g have fun.

Step 6: Release the Yeast

Most lean bread recipes call for around 1/2 to 1% yeast. This translates to 5g to 10g of yeast in our recipe. This is getting down to the range where many kitchen scales aren't that accurate but don't despair you have a couple of choices. First just measure it as well as you can and call it good. It will probably work out fine, this isn't rocket science. Second, visit your neighborhood drug dealer and use his scale. He has a scale which is accurate to hundredths of grams. Or if his pit bull is giving you a dirty look you might want to get your own, they aren't expensive. If neither of these choices is appealing you can do what I do. A teaspoon is about 3g of yeast and a tablespoon is about 9g. I use a teaspoon for bread that I am going to proof for a couple of hours or retard overnight in the fridge and a tablespoon for bread that I want to rush so I can bake it faster. This works best for flat breads like pizza and naan which don't rise much after they have been formed.

If you are still buying yeast in those little packets you are being used. Buy it in 1 pound packages and store it in the freezer. It lasts for years. Keep a small supply handy in a mason jar in the fridge.

Step 7: The Need to Knead

If you make bread more than once in a blue moon you really should get a Kitchenaid stand mixer. They are amazingly powerful and virtually indestructible. They are also heavy, bulky and expensive as well, but with reasonable care you will probably only need one in your lifetime. With a stand mixer and a dough hook you just dump everything in the bowl and let it rip for a few minutes. You sometimes need to scrape down the bowl and occasionally the dough may climb up the paddle and need to be subdued but it is generally pretty trouble free.

If you are working by hand or even with a mixer you can save yourself a lot of work by just barely mixing the dough and then letting it sit for about ten minutes before you knead. This gives the flour time to hydrate which is half of what you are trying to accomplish. It makes your dough much easier to work. The popular no-knead recipes take this to the extreme. Wait long enough and you don't need to knead at all.

Cover your dough and leave it in a warm place for a few hours or, if you are blessed with patience and foresight, put it in the fridge overnight. The flavor will improve with a long slow overnight fermentation.

Step 8: Bake Off

For this example I made my dough into a couple of pizzas but you can adapt this technique to any type of bread you like. I use an electric oven at max temperature (550f) and after years of breaking pizza stones I now bake on a sheet of 1/4" steel. It doesn't need to be anything fancy. Mine is a piece of scrap from my shop. The steel transfers heat much faster than masonry which helps crisp nicely even though the oven isn't really as hot as I would like. It's no wood burning brick oven, but it makes some pretty good pizza.

Step 9: Summary

So there you have the only bread recipe you need you know. You've probably got it memorized already. You can whip out an infinite array of breads This is a great technique for experimenting and developing new recipes. Just weigh out a kilo of whatever blend of flours you want add your yeast and salt and pick your hydration based on what you want your bread to be like. You can amaze your friends! (assuming they are amazed by such things)

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    99 Discussions


    1 year ago

    Great i'ble!!

    Everything described in good detail!

    Great instructable!
    Ive always tried/wanted2bake bread tho they never workd out.
    The percentage method simplifys immensly. I even realised straight off u were talking bout percentages of the total! Its a empiric recipe which makes the process so easy. Thanks,
    A future baker...

    I was following until you mentioned going to a drug dealer.


    Great Instructable nicely explained...
    I shan't be trying it though, my wife won't allow me in the kitchen. I'm only allowed to walk through it to get to my workshop.
    FYI in the UK we call 'metric' bread... Bread ??

    Many thanks for this great instructable!

    Trying here to cut down on white flour. Any tips for how to adapt percentages when using wholewheat or other "healthier" types of flour (rye, spelt etc.) -- either 100% or combined with white flour?


    2 replies

    I definitely understand trying to get away from white flour. You can use this baker's percentage technique with any flour or combo of flours you like but it may require some adjustment. Whole wheat flour generally absorbs more water than white flour so you will want to up the hydration by a couple of percent. Many 100% whole wheat recipes also add some oil as well which helps keep your bread from coming out like a brick.

    It is pretty much the same for any kind of flour I think. In Step 9, he wrote : "Just weigh out a kilo of whatever blend of flours you want [...]"


    1 year ago

    The proof of the 'math error' is the simple fact that " flour" being 100% of the mixture leaves NO room for any thing else!!

    This leaves flour as being ONLY 100 MINUS the sum of 70% + 1% + 2 %

    or flour being : only 73% of the mixture... so, flour is merely only 73% of the final mixture..

    Therefore 73% + 27% flour = the 100% of the mixture.... by weight.

    this yields 100%.

    5 replies

    Add an egg and that's crepe batter!

    french crêpe batter is 250g flour, 4 eggs, 0,5l milk, no salt, no yeast, no sugar - everything else is pancakes;

    Your error is thinking it refers to a percentage of the whole. In fact it refers to the percentage of each ingredient relative to the amount of flour. The percentages are not intended to add up to 100.

    Don't go backwards. Go forwards and you can make any amount the "100 percent" its well explained.


    1 year ago

    Hah hah hah! It's about time someone extolled the virtues of both baking bread by baker's percentages and using the metric system. This country is the only industrialized nation that still uses the king's measurement system that is so arcane and unwieldy to use. I avoid recipes that use volume measurements. Weighing ingredients, like most of the world does, is not only more precise and accurate, it easily allows making adjustments, getting consistent repeat results, simple scaling of a recipe, and sharing recipes that work for everyone. Volume measure in breadmaking is inherently inaccurate because flour densities vary widely. You never know what percentage the dough has. I'm amazed at how many bread books by alleged experts use only volume measure.

    I bought a digital scale a few years ago at Costco for $15 and use it all the time, especially for bread. As you say, you don't need a recipe for bread dough. Just decide how much flour you want to use and what percentage of water and weigh away.

    I bake bread and pizza in a toaster oven and I also have a 1/4" piece of steel that just fits the rack. A 12" pizza, loaded, bakes in 4 minutes to charred perfection.

    4 replies

    I concur whole heartedly with you on the USA not widely using the metric system. But did you know it actually IS the official measurement system in the USA, and has been since 1893?

    Also, we actually do use metric system in the United States a lot more than most people realize. For example medications are all dispensed CCs, miligrams and milliliters. Film stock is measured in millimetres, as are some ammunition rounds. Soda and wine comes in bottles measured in liters or milliliters. Food labels utilize metric units. Look around and you'll be surprised at how common it actually is.

    There was a push to move the United States into the metric system back in the 1970s, but it was killed in 1982 by President Reagan. I never understood why, but my father-in-law always felt that it was blowback from the machinist unions who had a great deal of money invested precision Tools all calibrated to imperial units.

    The pushback from machinists is ironic considering they measure everything in thousandths of an inch (or milli-inches as I called them during my brief internship in a machine shop). My teacher/head machinist wasn't as amused as I was. :)

    That's very interesting. I did not know that. Yes, I am aware that a very few products are sold in metric quantities but I'm talking about universal adoption. And I have heard the machinists argument. But that's no excuse IMO. Using base 10 instead of base 2 measurements highly simplifies mental arithmetic. A perfect example—the other day I was in Costco and I was considering two different options for the same product. One was like 3 x 1lb 12oz packages for $x.xx, the other was, say, 2 x 2lb 10oz for $y.yy. How the hell do you determine the price per oz in your head so you can decide which is the better buy? And they do that on purpose. If it were metric it would be easy. The so-called imperial system is antiquated and based on some English or Scottish king's thumb (or other organ LOL!) size. Even the UK switched over to metric decades ago. I order things all the time on eBay that are metric so this further complicates things. I cannot find a metric drill bit set at Home Depot, Lowes, or Harbor Freight. I'll have to order one from China on eBay. Yet these companies do sell metric fasteners.

    I concur wholeheartedly. Imperial units suck. So much easier and more practical to use base 10. Our country needs to get its cranium out of its posterior and get on the same page as the rest of the world. Alas... We Americans FEAR CHANGE. :/

    Weighing isn't necessarily "exact" either. Packing density affects flour quantity measured by volume, flour initial water content affects quantity when weighed. Damp flour has less flour per unit weight then dry flour!

    As for salt, are you trying to kill everyone consuming the bread? I make bread without salt all the time. 20g of salt is way too much sodium! Why is salt needed in a pizza where salt-laden sauce, cheese, pepperoni, etc. are added on top? Entrees made from multiple ingredients should have salt in ONE ingredient. I am not interested in gorging water for the next 2 hours after eating the bread of pizza!