By Tom Cooper

Stick-tight is a term used to describe nuts in their green husk which stay attached to the fruit stem, or raceme when fully ripe. This can cause another problem called "pregermination" which is the opening of the germination seam of the nutshell allowing the seed to start the growing process. When this happens the nutmeat shows a green discoloration at the opening which is "cyanogenic" (bitter tasting, and poisonous in large amounts) and those nuts should be discarded.

It is important to keep the area around and under the leaf system of the tree free from weeds and leaves in order to gather the nuts easily. The nuts should be gathered weekly. This will reduce the possibility of insect infestation and start the drying process sooner. If you have more than one specie of Macadamia tree, keep the nuts separate. Differences in oil and carbohydrate levels could cause scorching of the mixed nuts when roasting.

Why dry the nuts? The reason is, when ripe, the cellular material that stores the wonderful essential oils of Macadamia still has a residual moisture content of 20 to 25%, and in order to enhance this flavor it is necessary to remove all of the excess moisture. Industry standards reduce moisture content to 1 ½ %. This gives the nutmeats their characteristic bite or crunch. Most Macadamia varieties have around 75% oil content.

To dry small amounts of the husked nuts, I recommend using ¼ inch hardware cloth (actually a woven or galvanized wirecloth) basket. Use this wirecloth and staple it to a wooden frame so you have a container that will hold a substantial amount of nuts and provide adequate ventilation to assist the drying process promptly. Construct these appliances to a size that will provide you adequate drying area for the production of your trees. Do not fill the nuts in the trays more than two deep in order to provide more prompt drying. Place them in a well-ventilated location that has heat, which can accelerate the drying process. It is important that you do not place them in direct sunlight as this causes other drying problems, to avoid rehydration they should be covered at night. What happens in sunlight is an excess of heat that causes the nutmeat to cement itself onto a side of the shell and this makes it difficult to separate it when it is shelled. Excess high temperature (above 110F) will cause the nutmeats to form a seal on the outer part of the actual nutmeat, which will not allow the remaining moisture to escape, and this ruins the meats as they resemble little rubber balls, and will dry further and must be discarded. Ideal drying can be achieved by a strong flow of air at a temperature not to exceed 110F for 100 hours continuously. It is best to start at a temperature of 90F and two days later increase to 100F, then a day later 110F. This process should not take longer than five days with nuts wet off of the tree. If you cannot approximate the previous formula, the ambient temperature of garage rafters may work for storage. After these drying steps have been completed it is time to crack and sort the dry nutmeats.

The recovery rate of nutmeat versus shell is variable, percentages can be as little as 10% to a high of 40%.

Crackout is a common industry term to define this percentage. Shelling reduces the volume by this same formula for storage. This is a good reason to completing all the processing steps.

A word of caution is necessary at this point. Macadamia nuts in shell that have been dried correctly can and will rehydrate (re-absorb moisture from the air). It is very important at this time to either continue processing (shelling and sorting), or store in an oxygen free environment. This will also prevent or slow oxidization of the essential oils in the nutmeats, this can also be described as rancidifing of the nutmeats. Rancidification occurs at a rapid rate, particularly in improperly dried nuts after they have been removed from their shells. We store the nutmeats in gallon size ziplock plastic bags after the shelling and sorting process is complete and find that the gallon size holds five pounds of product which then is easily stored in your freezer. Place the nutmeats in your freezer and they will have a life of over five years and retain the "off the tree" freshness.

When removing from the freezer, take only the amount of nutmeats you plan to use, place these immediately into another airtight container and allow an hour or so to adjust to room temperature, then these nutmeats will be ready to use. The reason is that the frozen nutmeats removed from the freezer and placed in an open container will rehydrate and immediately become soggy and less flavorful. The term for the product at this time is described as raw, and edible.

If you want to enhance the flavor more, roasting is the next step. To roast the nuts may require some experimentation with your own equipment in order to find the best approach. I have evolved a technique that works well for me and is able to roast twelve pounds of nutmeats at one time. A convection oven is the key to good dry roasting. A convection oven is one, which has a fan usually in the rear, and as you bake in the convection mode the heated air is vigorously circulated throughout the oven. This circulated heated air uniformly roasts the nutmeats in larger quantities and minimizes scorching which is so common in the bake only mode. I use an oven temperature of 300F.

I have experimented with roasting in a microwave oven. I have had good results particularly with small amounts of nutmeats. My method is use a four-cup microwave safe container and fill to the top with the nuts. Roast in one-minute intervals, remove from the oven and pour into another container, stir, and return to the microwave. Do these four times, or a total roasting time of four minutes. This method works well.

I formed a basket from the ¼ inch hardware cloth 12" x 18" x 3" high to roast the nuts in and this basket holds around 12 pounds of nutmeats.

Fill this basket, place in 300 degree Fahrenheit oven and roast five minutes. Remove basket and toss the nutmeats in a large pan and return to basket and oven for another five minutes. Do this four times for a total roasting of 20 minutes. Some nuts will take more or less time in the oven so do a trial run and always stop early rather than adding more time to preclude scorched nuts. Roasting time in a regular oven will be slightly longer so work accordingly. A good guide for proper finished roast is when the nutmeats collectively are a golden yellow. The nutmeats will continue to cook after being removed from the oven so be careful not to over cook.

Some people butter and salt the roasted nuts, but these nuts with 75% oil content do not require any additional oil or fat. Salting is personal choice. If you do salt them, powdered bar or kosher salt will adhere best when applied to nutmeats that are still hot, as the natural oils in the nutmeats will attract the salt.

Bon Appetite!

This fact sheet is a courtesy of Cooper’s Nut House

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