Next, we’ll see how cure olives for remove bitterness and prepare to table olives, in two different ways.
Green olives have a very bitter taste that makes their direct consumption impossible. Therefore, it is necessary to subject them to a process called cooked or cured. This process makes it possible to sweeten the olives by breaking down oleuropein (guilty of the characteristic bitter taste of green olives).
Once collected the olives from the tree, we can sweeten them using caustic soda or by frequently changing the water
Elimination of bitterness using caustic soda
To eliminate the bitterness of the olives, we have to put them for several hours in a solution of caustic soda and water. The time required to sweeten the olives will depend on their size and variety (Chamomile, Gordal Sevillana, Hojiblanca, Morisca…).
Classification of olives
When the olives arrive at the entamadora they are classified with precision machinery. Smaller olives ( zofairones) or that have some small defect are discarded and used to produce EVOO. Although green olives give poor oil yield, the quality produced is usually very high and the oil sales prices are good.
Measure to cure olives with caustic soda
Although establishing the ideal dose of caustic soda per kilo of olives requires great experience and consider multiple factors. The demands of the industry to obtain perfectly homogeneous olives are much higher than those necessary to prepare excellent homemade olives.
Typically, add 20 to 40 g of caustic soda per kg of olives depending on size and olive class. As a standard measure to cure caustic soda olives, we can take 30 grams of sodium hydroxide per kg of green olives. Cooking black olives is unusual, but in this case the amount of soda used should be reduced to half. The pulp of black olives is softer and the sodium hydroxide penetrates more easily.
If we go through the sodium hydroxide we can overcook and damage the olives during the curing process. On the other hand, if we fall short, cooking time will have to be longer to eliminate bitterness.
Remove bitterness from olives with sodium hydroxide (NaOH)
Before introducing the olives in sodium hydroxide, it is important to dissolve the caustic soda in water. We must be careful, read and follow the manufacturer’s handling recommendations.
The sodium hydroxide is dangerous and we should not come into direct contact with it.
Therefore, it is advisable to wear gloves and glasses to protect yourself. It is also important to be careful and avoid splashing when adding the caustic soda to the olives.
In the homemade elaboration of olives the habitual thing is to go checking periodically the penetration of the sodium hydroxide in the olives. To do this, it is enough to split the olive concentrically, the caustic soda reacting with the pulp of the olive forms a ring that approaches the bone.
When it reaches the bone we know that the sodium hydroxide has acted throughout the olive. However, it is advisable to change the water a little before the caustic soda reaches the olive bone. 3/4 of distance is enough to eliminate the bitterness and get the olives to remain hard for a long time.
The time it takes to penetrate depends on the size of the olives, so homogeneous sizes give better results. We advise you to do the first test before 6 hours and then more frequently.
It is important that the olives are not longer than necessary in contact with the sodium hydroxide solution. Prolonged exposure will soften the olives for overcooking.
Once the olives are cooked with caustic soda, we must change the water 2 or 3 times a day until it is clear (approximately for 3 days). At this time we will have removed the remains of sodium hydroxide and the olives will be ready to dress.
The pot olives that we consume most commonly, in addition to the process of cured with caustic soda, go through a lactic fermentation phase before being marketed.
How to cure olives with water
It is clear that cure olives simply with water is more natural and does not pose the danger of handling caustic soda. However, sweeten olives without sodium hydroxide, is much more laborious, expensive and also requires a longer waiting time.
On the other hand, it is difficult to remove the bitterness of the olives completely and this may or may not like us.
The most common way to cure olives with water is to crack or crush (“male olives”). This process has the purpose of increasing the contact surface of the olives with the water, favoring the bitterness of the olives dissolving in the water. The variety of Verdial olives is usually aligned in this way.
Although olives can also be sweetened without crushing or cutting, the process lasts for several months.
To prevent the olives from being damaged, it is necessary to keep them in brine.
Keep the olives in brine
Once we have managed to remove the bitterness of the olives, the brine is essential to preserve the cured olives in perfect condition. When we are not going to immediately consume the harvested olives, we can keep them in brine without curing, maintaining their hardness.
It is important that the olives that we are going to keep do not come into contact with the air, for this we can introduce them in jars or carafes. Another trick to prevent air from oxidizing the olives is to put a plastic bag over them.
Using brine, we can keep olives for the whole year in perfect conditions. Homemade olives are usually preserved without dressing in brine.
How to make olive brine?
The proportion of salt needed to preserve olives in brine is approximately 100 grams of salt per kg of olives.
The method traditionally used to check the brine is to place a fresh egg in the water and dissolve salt until it floats. In order to use this technique successfully, the egg must be of recent posture, since eggs that have been laid for a long time also float in the salt-free water.
Over time, the olives absorb part of the salt and the salt concentration of the water drops 40-50%.
However, it is not necessary to continue adding salt, the initial concentration is sufficient during the fermentation of the olives.
Excess salt problems: It can produce the wrinkled olives and alter the fermentation speed.
Consequences of insufficient salt: when the salt concentration in the water drops below 5%, fungi and other agents that prevent the good preservation of olives can begin to act.
Brine is widely used in the entamadora industry to preserve olives throughout the year.
Curing Olives in brine: Lacto-fermented
Although usual when making homemade olives, it is to consume the olives after removing the bitterness to the olives and eliminating the caustic soda. At the industrial level, a lactic fermentation process must be carried out. To do this, the cured olives are kept in brine for 2 to 5 months. The fermentation rate decreases with low temperatures.
The lactic fermentation of olives converts the sugars or carbohydrates of the fruit into lactic acid. During this phase, yeasts produce carbon dioxide bubbles. Lactic acid, together with other components derived from the fermentation carried out by lactic bacteria, help preserve and protect the olives of various microorganisms. This acid lowers the pH of the water and acts as a natural preservative for the olives.
Once the Lacto-fermented is finished, the olives will be prepared for sale.
To preserve the olives in perfect condition, once the fermentation phase is finished. Experts recommend to add 30-40 grams of salt per kg of olives.
The olive greening season is approaching and we will soon be able to enjoy homemade olives again.
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