Monday, 4 April 2011

Yeast Goods

I'm going to post a hot cross 'muffin' recipe soon, but first a word on yeast goods.

Yeast:
  • Dried active yeast can be substituted for Fresh yeast  -just half the amount (if recipe calls for 14g fresh yeast, use 7g dried)
  • For most recipes yeast can be added directly to the flour-no need to mix with waster first (the old type of dried yeast needed this action but fast acting dried yeast and fresh yeast usually don't)
  • When weighing dry ingredients directly in the bowl, the yeast and salt must avoid contact-salt 'eats' yeast.
  • Most supermarkets sell yeast in boxes of 7g sachets-my recipes are adjusted accordingly- yeast quantites are in multiples of 7
Temperature:

'Base Temperature'
In bakeries, where product consistency is very important, we use what is called the 'base temperature' to determine the ideal temperature of the liquid in a yeast recipe.

Different doughs have different base temperatures, but for most simple yeast doughs, the base temperature is 56C. This means the Celsius thermometer readings for the liquid plus the air temperature plus the flour temperature should add up to 56C.
i.e , LIQUID TEMPERATURE  + ROOM AIR TEMPERATURE + FLOUR TEMPERATURE=56C.

so to determine the liquid temperature , following formula is used:

 (the room temp + flour temperature) - 56 = temperature of liquid

This temperature taking is often unnecessary in the home unless you have a  very warm or very cold kitchen.  For a room temperature of 16-21C, the flour will usually be about the same temperature as air so the water from the tap is ideal-this is usually at a temperature of about 13C.

'Dough Temperature'
 Most recipes call for tepid water-this as explained above is usually undesirable-mixing generates heat and your 'dough temperature' after mixing should usually not be more than 25C.

Recipes that call for tepid water in basic yeast recipes usually do so to speed up the raising or proving process-when in actual fact, the slower the first (see below) rise, the better the product.

Rise or Prove
There are usually two proves with yeast recipes, the 1st prove is just after mixing, the second is after 'shaping' .  The slower the 1st prove the better the taste.  So most recipes can have their 1st prove overnight in a refrigerator.
The second prove can take place in an airing cupboard-this temperature of about 24C is ideal.  It is important not to over prove though, too much rise will give a fermented taste and poor structure.

Flour
Flour is hygroscopic-it retains moisture and so the amount of water it can hold can change on a daily basis.  it is for this reason the same recipe can work one day and not another.  The solution to this is to keep about 50ml back or maybe add another 50ml or so.  But you must decide to add or hold back water early on-adding it too late into the mixing process can mess up your bread/buns.

The flour to use is strong flour (T65).  This flour has a high gluten content-it gives bread its strength and structure, its the scaffolding in bread. and the more you mix the more you produce.  It is for this reason for non yeast goods, such cakes,  scones, soda bread and biscuits, you don't over mix- gluten produced in these non yeast goods will give a heavy  texture.

Resting
after the first prove you cut the dough into desired portion size.  the pieces are then allowed to rest before shaping usually for 10-15minutes.  this resting allows for easier manipulation of the dough and therefore gives better results.

Shaping
Shaping of the dough is important-I'll give directions for shaping with each yeast recipe
 When dusting the surface of the work table, rice flour is an excellent alternative to flour.

Salt and fats:
Salt adds flavour, gives colour and helps crust formation.
Fat, usually butter gives flavour and softens the crust and dough.
I was taught to add these after the initial mix, but usually I don't find it makes a difference (except of course in the case of yeast goods like brioche of course)

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