Prior to use, the calabash gourd needs to be specially prepared by a curing process. Curing eliminates the remains of the calabash pulp from the inside. The pulp of a mature calabash has very strong laxative properties and needs to be removed to prevent unsuspected and unattractive side effects. Additionally, during the curing process the walls of the calabash container absorb the essence of yerba mate.
A newly purchased calabash gourd should be washed first with warm water. It should then be filled to ¾ of its capacity with dry mate and then filled with hot water. After the dry leaves have absorbed some of the water, the container is topped up to the brim. If the vessel has a virola ring around its rim, the water should not reach up to the virola. The gourd is then left in a safe place for 24 hours during which we should check whether there is any leakage which would suggest that the container is cracked. The gourd will ‘sweat’ slightly underneath its bottom but this is quite normal. If that happens, more water should be added to keep the calabash full. After 24 hours the leaves are thrown out, the container is lightly rinsed and the pulp is removed with a small spoon. The calabash is then carefully rinsed again.
A calabaza gourd should be cured twice by adding fresh leaves, filling with hot water, letting it sit for 24 hours and then cleaning. Some people believe 24 hours to be enough but others recommend 4 or 5 days. Porongo gourds need just one curing session.
There are also those who believe that previously brewed leaves should be used for the curing process, simply to save mate. However, old leaves may be fermented or affected by fungus which might damage the gourd. I recommend that dry leaves be used for this once-only process.
Whilst curing a calabash gourd is absolutely necessary, curing palo santo vessels might not be. Some people believe that a good wash with boiling water is enough but others recommend a specific curing process to minimise the risk of cracking, although it will not eliminate this risk entirely.
A palo santo mate gourd can be cured as follows:
1. Rinse the container with water.
2. Leave it to dry completely.
3. Cover the inside wall of the palo santo with butter or olive oil.
4. Let it stand for 2-3 days.
5. Wash the container carefully with hot water to remove all traces of fat.
To prevent cracking, care should be taken when using the palo santo cup. First of all palo santo should not be used for hot mate unless it has a complete metal coating. Coated palo santo rarely cracks but even if it does it can still be used. Secondly, it should be kept at constant humidity. It is advisable to use it every day and leave wet leaves in the container until the next day use. If not used for a longer period, where the humidity might change, palo santo may be emptied and dried but the drying should be slow, again to prevent cracking.
Palo santo wood has a high content of resin which might come to the surface of the container looking a little bit like icing on a cake. This is a natural process and should not cause any worry.
These vessels need only to be carefully washed prior to use. No other special treatment is necessary.
Guampa made of horn should be soaked for 24 hours in water with washing detergents and then carefully rinsed.