Olive açma and pastries stay fresh a day longer than plain ones. That observation is accurate and two separate mechanisms lie behind it.
How does staling happen?
Staling does not mean drying out.
Bread kept in a sealed container stales too, without losing water.
The real mechanism is starch retrogradation.
During baking the starch granules take up water and gelatinise.
That gives the dough softness and elasticity.
As cooling begins the starch molecules start rebuilding an ordered structure.
That process is slow but continuous.
Recrystallising starch releases the water it held.
The water separates from the crumb without evaporating; it passes into the crust.
The result is a hardening interior and a softening crust.
That is the classic picture of staling.
How does fat delay staling?
Fat inserts itself between the starch molecules.
That makes it harder for those molecules to reorganise.
Crystallisation slows and water stays bound longer.
Fat also coats the starch granules.
That coating prevents the granules approaching one another.
The size of the effect depends on the quantity of fat.
Fatless bread stales markedly within a day.
A dough containing 10 percent fat stays fresh three or four days.
In an olive dough the olives bring additional fat.
A hundred grams of olives adds 10 to 15 grams of fat.
Adding 200 grams of olives to a kilogram of dough means roughly 2 to 3 percent extra fat.
That looks small but the effect is measurable.
| Factor | Effect on staling | Mechanism |
|---|---|---|
| Fat | Delays | Blocks starch crystallisation |
| Salt | Delays | Binds water |
| Sugar | Delays | Binds water |
| Dairy | Delays | Fat and protein |
| High humidity | Delays | Less water loss |
| Cold storage | Accelerates | Crystallisation speeds up |
What does salt add?
That is the second mechanism and the less known one.
Salt binds water molecules to itself.
Bound water cannot participate in starch crystallisation.
Salt also slows the evaporation of water from the dough.
Olives are markedly salty: 700 to 1500 milligrams of sodium per hundred grams.
That salt passes into the dough during baking.
The area of dough around each olive stays moister.
That is a local effect, but it spreads through the product.
Salt has a second effect too: it slows microbial growth.
That delays mould and makes a separate contribution to shelf life.
But that contribution is limited; because the olive proportion is low, the total salt does not rise much.
Is the brine a problem?
Olives carry brine, and that can create problems in dough.
Wet olives bring excess water into the dough.
That water disturbs the consistency and creates steam during baking.
The steam leaves voids around the olives.
Ring-shaped gaps appear around them on the cut face.
The salt balance of the dough is disturbed too.
The solution is simple: the olives should be drained and patted dry.
Fifteen minutes in a colander and then paper towel suffices.
Excess oil should be removed from olives packed in oil as well.
Olives should be added chopped; whole olives both leave voids and cause problems in slicing.
A piece size of five to eight millimetres suits.
What proportion of olive oil should be used?
The quantity of olives determines both flavour and structure.
A range of 150 to 250 grams for every kilogram of flour works well.
At that level the olives give a clear flavour without disturbing the structure.
Above 300 grams the dough becomes heavy and the rise diminishes.
Olives physically interrupt the gluten network.
Too many reduce the dough's capacity to hold gas.
The salt level rises too, and salt suppresses yeast activity.
Where 250 grams of olives go into a kilogram of dough, the dough's own salt should fall by roughly a third.
Without that calculation the product comes out too salty and proving slows.
The proving time should be extended slightly as well.
Which olives should be used?
The variety affects the result.
Black olives are softer and fattier; they disperse more easily in dough and contribute more fat.
But they darken the dough when crushed.
Green olives are firmer; they hold their shape and show more clearly on the cut face.
But their salt is generally higher.
Stoned olives must be used; an unbroken stone is a serious risk.
Where stoning is done at home it should be checked carefully.
Olives packed in oil can be preferred; they carry less brine and their oil contributes to the dough.
Spiced olives can be used, but the spicing changes the flavour of the dough.
That should be a deliberate choice.
What about storage?
Olive pastries keep a day or two longer than plain ones.
Two to three days at room temperature.
They should be stored in a paper bag; plastic traps moisture and the crust softens.
A bread bin is a good option.
They should not go in the fridge.
That is a frequent mistake; fridge temperature accelerates starch crystallisation.
A product kept a day in the fridge stales as much as one kept three days at room temperature.
Freezing is the best route for long storage.
Starch crystallisation stops in a freezer.
Baked product keeps three months.
A short spell in the oven after thawing restores the texture almost entirely.
Five minutes at 180 degrees suffices.
In raw frozen production the product is baked without thawing and the result comes very close to fresh dough.
How is the proportion of olive oil set?
Olive oil determines both taste and structure in a dough.
The proportion runs 15 to 30 percent of the flour weight.
At a low proportion the dough is more elastic and rises more.
At a high one it becomes more crumbly with a shorter texture.
Fat coats the gluten strands and limits the formation of the network.
That softens the product, but too much weakens the structure.
Above 35 percent the dough cannot hold its shape.
The aroma of the oil is a variable too; extra virgin brings a pronounced taste.
Where a neutral result is wanted, refined or mild olive oil is preferred.
The oil goes in after the liquid components; added at the start it prevents the flour taking up water.
Warming the oil slightly before adding it also helps it disperse evenly, particularly in a cold kitchen where olive oil can begin to thicken.
