1. Boil
the un-peeled potatoes.
2. Mash them into the cooking water.
3. Add remaining ingredients.
4. Cover with a cloth and leave for 3 days.
5. Use instead of yeast in your bread recipe.
For
further information about sourdough, visit
www.howstuffworks.com.
Quick
Yeast
The
easiest yeast to use is Quick Yeast, which is a fine granulated powder that
can be mixed straight into the flour. Use 3 teaspoon of quick yeast to 1.5kg
of flour.
Fresh
Yeast
Compressed
cakes of crumbly fresh yeast will keep for about two weeks in a
refrigerator. Discard fresh yeast if it has gone brown and hard. To activate
fresh yeast it is creamed into a sugar and water solution at about 35ºC
(95ºF). After 15-20 minutes the mixture will be frothy and ready to add to
your flour. Use 50g (2oz) fresh yeast for 1.5kg of flour.
Dried
Active Yeast
Is a
dehydrated form of compressed yeast with the appearance of small 1.22mm
spherical granules. It has a long shelf life, provided it is kept airtight.
It is activated in the same way as fresh yeast by whisking into a sugar and
water solution at about 43ºc (110ºF). The mixture will be frothy and ready
to use after 15 minutes. Use 1oz (25g) dried active yeast for 1.5kg of
flour.
Baking
Powder
It is the
chemical combination of an acid and an alkali in baking powder that produces
carbon dioxide gas which can raise baked goods. Commercial baking powders
sometimes contain an inert filler such as wheat or rice starch so check the
ingredients label if you are on a special diet or
make your own baking powder.
Historically baking powder is a nineteenth century invention. A famous
chemist, Justus Von Liebig, explored the relationships of organic chemistry
to agriculture and plant physiology. He was interested in obtaining maximum
plant yield and to control processing of grain without wastage. Instead of
using yeast he tried to raise bread with sodium bicarbonate and hydrochloric
acid, with uncontrollable, dramatic and sometimes explosive results.
He
eventually found the combination of sodium bicarbonate and
monoclacium phosphate, when mixed with water, would release carbon
dioxide at a controlled rate for successful baking. This is still the basic
formula for many modern baking powders.
Self
Raising Flour
The
correct proportions of the raising agents, acid and alkali, are already
added into self raising flour. The raising agents used at Doves Farm are
sodium bicarbonate and monoclacium phosphate.
Sodium
Bicarbonate (E300)
Sodium
Bicarbonate, sometimes called Bicarbonate of Soda, is an alkali and can be
used on its own as a raising agent if the dough or batter is sufficiently
acidic to allow a reaction that creates carbon dioxide. Lemon juice, yoghurt
molasses and sour cream are acidic enough to react with Sodium Bicarbonate
but may impart a distinctive strong taste to your baking.
Cream of
Tarter (Tartaric Acid E334)
Cream of
tartar is a fast acting acid that can be combined with bicarbonate of soda
to make your own raising agent.
Ammonium
Bicarbonate (E503)
This
alkali is sometimes know as 'vol' because it disappears during baking. It is
often one of the raising agents used in biscuit manufacture where the carbon
dioxide and ammonia combine to raise the biscuit dough. As a processing aid
the law does not require ammonium bicarbonate to be declared on the
ingredient label, however we will always tell you if we add it to a Doves
Farm product.
Make
your own Baking Powder & Self-Raising Flour
Place 3
teaspoons of bicarbonate of soda with 4 teaspoons of cream of tartar in a
jam jar and shake well. Use as required where a recipe call for baking
powder.
To make
self-raising flour, add 1tsp of baking power to 200g / 8oz plain flour.
Use gluten
free flour to produce gluten free self raising – this is suitable to
yeast-free diets
Yeast,
Gluten and Carbon Dioxide
Yeast is a
single-cell fungus that breaks down the starches in wheat flour, forming
sugar. This is fermentation. When the yeast works on the starch and
sugar molecules, it gives off carbon dioxide gas and alcohol. Yeast is a
leavening agent for bread. It is what makes the bread rise.
Flour
comes from any kind of ground grain, but most bread contains wheat flour.
Two proteins found in wheat flour, gliadin and glutenin, form a stretchy
substance called gluten. When you knead dough, you help gluten form
long, threadlike chains. These gluten chains help hold the carbon dioxide
gas in, creating those tiny holes that create the airy texture of bread.
The big
difference between sourdough bread and the "normal" bread you buy or bake
today is the source of the yeast. Most bakers today use cultivated yeast
that comes in a package. The package contains live yeast fungi in suspended
animation! The yeast has been dried, preserved and formed into a powder. You
add flour, water, sugar and salt to the yeast to make a loaf of bread. The
water re-activates the yeast fungi, which feeds on the sugar and starch to
make the bread rise.
Sourdough
bread deals with yeast in a completely different way. Sourdough yeast fungi
are actually kept alive constantly in a liquid medium called a starter.
The baker either captures wild yeast that floats in the air to create
starter from scratch or gets a cup of active starter from a friend and
expands it.
Catching
the Wild Yeast
Hundreds
of years ago, before there was packaged yeast, bakers used sourdough starter
to keep a supply of yeast alive and handy. They kept a pot of live culture
in a flour/water medium, and "fed" it daily or weekly so that the yeast
remained alive and active. To understand how sourdough starter works, let's
look at how you can create a batch of starter using live yeast that is
floating in the air!
To perform
this experiment you will need:
·
A pottery
crock, plastic container or glass jar, preferably with a loose-fitting lid
·
A wooden
spoon
·
A piece of
cloth
·
Some flour
(preferably without any preservatives in it) and water
To start a
culture, mix two cups of flour and two cups of water in a glass or pottery
bowl (in the old days, a baker probably had a special clay crock for
starter). Lay a cloth over the top and let it sit on the kitchen counter. It
turns out that there is yeast floating in the air all around us all the
time, and some of this yeast will make its way to your flour/water mixture.
It will then start growing and dividing.
After 24
hours, you pour off about a cup of the mixture and feed it with another cup
of flour and another cup of water. In a few days, the mixture will become
frothy as the yeast population grows. The froth is caused by the carbon
dioxide that the yeast is generating. The starter will also have a bacteria,
lactobacilli, in it. This lends to the slightly acidic flavor of the bread
by creating lactic acid! The alcohol that the yeast creates and the lactic
acid together are the source of sourdough bread's unique flavor!
A common
question at this point is, "why doesn't the flour get infested with all
sorts of mold and bacteria and become a disgusting health hazard????" For
example, if you put a bowl of sugar water or orange juice out on the
counter, that is exactly what would happen. It turns out that the starch in
bread flour is something that not a lot of bacteria can easily handle, while
sugar is (see
How Food Works for some details). Yeast,
on the other hand, creates special enzymes to deal with starch. The yeast
and lactobacilli also "poison" the culture with the alcohol and lactic acid
they produce, and that keeps other bacteria out.
Leave the
starter on the kitchen counter for five days. As the starter ferments, it
will develop a strong aroma -- bready and alcoholy and not particular
appetizing. Feed it every day or two by dividing it in half and adding a cup
of flour and a cup of water to one half of it (you can throw the other half
away). When you see a watery substance floating to the top, stir it.
Sourdough bakers call this "hooch." Over the week the starter became a thick
liquid, like pancake batter. It will be slightly yellowish.
At this
point you can do one of two things:
·
You can
store it in the refrigerator to slow down the yeast. Then you will only have
to feed it every 5 or 6 days.
·
Or keep it
on the counter and feed it every day.
·
If you
don't like the "wild yeast floating in the air" idea, there are other ways
to start a starter:
·
Get a cup
of starter from a friend or another baker. You take a cup of the starter and
add flour and water to make more of it. The starter can go on for years.
·
You can
make a starter with normal packaged yeast you buy at the store. Start the
same way as described above and simply add a package of yeast to it.
·
Or you can
buy a packaged sourdough starter mix at the grocery store or by mail-order.
Some
starters use milk instead of water, and some starter recipes call for sugar
or honey, which boosts the fermentation. There are starters that use
potatoes, too. Potatoes have starch in them, and that supplies more sugar
for the yeast to feast on.
When it
comes time to bake bread, you add a cup of this live culture to the dough to
provide the yeast needed to leaven the bread. You replenish the pot by
adding back an equal amount of flour and water, and regular feeding keeps
the culture alive.