Expression

With some kinds of plant material, there's no need for solvents or heat at all. You can simply squeeze the flavoring compounds out of the plant material. Citrus peels are the best-known example.

Many of the intense flavors and scents we want are contained in the oils that permeate the outer surface (the zest) of citrus fruit. The white pith is bitter, so be careful to separate the thin, outer oil-bearing layer from it. You can do this with an ordinary kitchen grater, but a Stanley Surform ® Corner Plane is an even better tool. This small woodworker's tool not only cuts the zest off cleanly, it also collects the shavings neatly in a recess above the cutting blade.

The oils in the citrus shavings can be extracted either by soaking in a strong ethanol solution (see "Cold Soaking" above), or by subjecting them to extreme pressure. In this case, "extreme" means up to a tonne per square centimeter, (4 tons per square inch)! Surprisingly, you can generate these kinds of pressure easily at home, with a sturdy metal frame and a small hydraulic jack, as illustrated in Fig. 6-6.

The citrus zest placed on a strong metal tray, then a flat metal plate is placed on top of this and the jack placed on top. The jack and the plates are placed in the metal frame, the top bar adjusted to fit snugly, and pressure exerted with a few strokes of the jack arm. After 10 minutes or so, practically all the oils will have been squeezed out of the rind. Don't expect them to come rushing out in a flood, like oil from olives or juice from grapes, because the quantities are very small. Finally, wash the material into a container with a little vodka or 95% ethanol, straining out the zest, to leave a concentrated solution of the essential oils.

It may seem like a lot of trouble to obtain just a little citrus oil, but the flavors are so intense that you don't need much.

Solid infusion (Enfleurage)

Solid infusion is another very old method once used extensively by the perfume and cosmetic industry. It's the only really simple way can extract the scent from small quantities of flowers. The technique, known as enfleurage, is a process in which odorless fats or oils absorb the fragrance of fresh flowers. In the old times, both pork and beef fat were used, and the fresh-picked flowers were pressed against thin layers of the fat for a few days before being replaced by new, fresh flowers. The scent-laden fats were then dissolved in ethanol and the delicate perfumes were distilled off. It's an old technique and no longer widely used, but you might like to explore it if you're interested in making perfumes.

Solid infusion is another very old method once used extensively by the perfume and cosmetic industry. It's the only really simple way can extract the scent from small quantities of flowers. The technique, known as enfleurage, is a process in which odorless fats or oils absorb the fragrance of fresh flowers. In the old times, both pork and beef fat were used, and the fresh-picked flowers were pressed against thin layers of the fat for a few days before being replaced by new, fresh flowers. The scent-laden fats were then dissolved in ethanol and the delicate perfumes were distilled off. It's an old technique and no longer widely used, but you might like to explore it if you're interested in making perfumes.

Be careful! This technique involves distillation of ethanol in its final stage, and may be illegal in your area! You may wish to try other absorbent materials such as Fullers Earth (a fine powdered clay-like material that absorbs oils) and then extracting the scent materials by soaking in 95% ethanol.

We have to frankly admit that we haven't actually tried this technique ourselves, but it is so unusual that we had to mention it. If you do try it, remember that hydrocarbon solvents (unlike pure ethanol) generally have an odor that will swamp the delicate flower scents.

Brew Your Own Beer

Brew Your Own Beer

Discover How To Become Your Own Brew Master, With Brew Your Own Beer. It takes more than a recipe to make a great beer. Just using the right ingredients doesn't mean your beer will taste like it was meant to. Most of the time it’s the way a beer is made and served that makes it either an exceptional beer or one that gets dumped into the nearest flower pot.

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