Citrus fruits thrive during the winter months, adding colour to many dishes such as salads, desserts and main courses. As our growers ship a wide variety of citrus fruits of different sizes and colours, we understand that many questions can arise and we are here to help answer them!

Clementines and mandarins: what’s the difference?

Perhaps we should start with the big debate: what is the difference between clementines and mandarins? Short answer: they are all mandarins! Clementines are mainly very sweet mandarins that are usually easier to peel. Mandarins (such as the nova variety) are usually more difficult to peel and have a slightly more intense, less sweet, orange-like flavour.

Why can citrus fruits also be green?

You may wonder why some citrus fruits arrive green, but don’t be alarmed! The simple answer is that there must be a significant difference in temperature between day and night for the green colour to disappear. The night temperature must be cooler for this colour change to occur. Green citrus does not mean that they are not ripe, but that the temperatures were not cold enough at night. So if you eat an orange from a tropical area, it is most likely green.

Here is a more detailed explanation: when the outside temperature is warm, the roots of the tree must absorb more water, integrating more nitrogen. When the weather gets colder, the water absorption decreases and therefore the nitrogen concentration decreases, which causes the green hue to disappear. The change from green to orange of the skin is a consequence of the reversible transformation of the chloroplasts of the exocarp (skin) into chromoplasts. The concentration of carbohydrates inside the orange, as well as the nitrogen content of the peel, cause this transition (more nitrogen, more green). Consequently, they do not completely lose their colour until it cools down in the evening. This is a reversible process that occurs with late oranges that turn green in May/June, as the climate warms up and the tree has to absorb more water and nitrogen, which forces them to turn green again.

What determines the juice content and acidity level?

The acidity is substantially higher than the sugar content at the beginning of the season, and as the harvest days pass, the acidity decreases while the sweetness increases. The orange season starts in mid-November and ends around mid-May, with the exception of late oranges that can last until June. Oranges at the beginning of the season are usually more acidic than those at the end of the season. Since our growers pick the oranges and send them directly to you without intermediate storage, they may have a higher acidity when you first receive them, we suggest that you store the fruit for a couple of days and it will become sweeter. The juice content of citrus fruits varies according to the type and time of harvest. The juice content decreases as the season progresses, as the tree will begin to suck water from the fruit as the weather warms up.

How do pests affect the external appearance of the fruit?

Citrus fruits are susceptible to a number of pests that can cause damage to the outside of the fruit, but do not affect the taste. Due to pests and nutritional issues, some oranges develop skin diseases. Citrus “shrivelling” is a physiological change that generates small cracks and fractures in the softer parts of the skin. In the early stages of fruit growth, the main cause is the enzymatic breakdown of the albedo (white citrus peel) cell walls. When the albedo cells rupture, they cause fractures in the white part of the skin (inner skin), resulting in soft (and deep) spots on the outside. This is an external condition that makes the fruit more fragile.

The South African cotonet is a new pest that settles in the petiole insertion zone (the leaf stalk) and causes a change in the development of the fruit. At the moment there is no clear solution, however, it is known that it can be moderately controlled with biological control (other insects). Citrus fruits may show black spots or other insect marks, as growers do not use synthetic fertilisers or post-harvest treatments. This should be interpreted as a guarantee of quality.

Furthermore, at CrowdFarming we do not waste fruit, so lack of aesthetic appeal is not a valid reason not to eat fresh fruit. Farms are not factories, and fruits have different sizes for the same reasons that some people are taller or shorter than others: genetic diversity and environment. Some fruits get more water than others, some get more sun than others, and some just stay small because of their genetics.

What is the best way to preserve citrus fruits?

Citrus fruits should always be kept in cool and dry places. It is essential to monitor the evolution of the fruit and to consume first those that are getting soft or have any marks that may cause them to rot. Although it is not necessary, keeping them in the fridge can extend their shelf life. If your box contains a mouldy orange, it is not necessary to throw away the whole box, although the surrounding ones will be stained. As the stains are fungal spores, you should clean the oranges. If they are stored for a long time in a humid environment with higher temperatures, they are more likely to become mouldy over time. Lemons should arrive firm, as this indicates that they are “turgid” (swollen) and full of water. If they become dehydrated, they may soften over time. 

All fruits available at CrowdFarming were grown without the use of synthetic pesticides or post-harvest treatments, and therefore do not include synthetic chemical treatments on the skin. This means that the peel can be used in cooking, but must always be washed.

We hope we have been able to answer some of your questions and that you find this information useful when selecting and enjoying your citrus fruit. The traditional food supply chain has led us to believe that oranges must be bright orange to be considered suitable for sale, but together we can change this mindset and start valuing what really matters: fruit grown naturally, passionately and perfectly imperfectly.