Ultrasonic Preparation of Bitters
- Bitters are very intensely infused alcoholic mixture used to flavour cocktails and other alcoholic drinks.
- Ultrasonic extraction and infusion helps to create an intense flavour profile in bitters.
- Whilst the traditional infusion of bitters is a time-consuming process, ultrasonic infusion is rapid and produces superior flavours.
In contrast to drinkable bitters such as Amaro, cocktail bitters are counted as non-potable bitters. This means that they are normally not ingested undiluted, but instead are used in small amounts as seasoning. Made from botanicals and a high-proof spirit, they are used typically used as cocktail seasoning, adding them in drops or dashes.
Ultrasonic extraction increases the release of bittering agents and their diffusion speed significantly.
Various botanicals such as roots, barks, spices, herbs, and fruits are common ingredients in bitters. Aromatic compounds, which give the bitters their unique taste, are extracted from the plant material (e.g. gentian, clove, orange peel). Bitters can be made from either one bittering plant or as a complex tincture including various botanicals.
The alcohol, normally a high-proof spirit, acts as solvent, which absorbs the flavouring, bittering components. Commonly used high-proof spirits for the preparation of bitters are vodka, rum, whiskey or cognac. As a general rule, vodka and gin are used for lighter bitters, whilst whiskey, rum and brandy are used for stronger bitters. High-proof alcohol helps to preserve the concoction of ingredients and gives a virtually infinite shelf life.
Bitters are mostly complemented with a small amount of added sugar or syrup to obtain a round, smooth flavour of the final product and diluted with water to the desired flavour intensity.
Step-by-step: Ultrasonic Preparation of Bitters
Step 1: Macerate the dried botanicals by grinding or crushing them into a fine powder. Typical methods of maceration include mortar and pestle, spice grinder, or coffee grinder. By macerating the dried plant material, the overall surface area of the botanical matter is increased. The increased surface area allows for a higher interaction of plant material and the alcohol (solvent) so that the flavour ingredients can be transfer more completely into the spirit. This is key to obtain a flavourful bitters.
Step 2: Soak the ground dried botanical material with alcohol. Therefore, the plant powder is placed into a glass beaker and the spirit (e.g. high-proof alcohol such as vodka, which has no strong original taste) is added. For 100g of plant material, use approx. 600mL of high-proof alcohol.
Step 3: This botanical alcohol mixture is ready for steeping. For the ultrasonic extraction and infusion of approx. 500mL to 1L, the ultrasonicators UP200Ht (200W) or UP400St (400W) are a good choice for an efficient and rapid steeping process. Insert the ultrasonic horn (sonotrode) into the beaker and sonicate the liquid for approx. 3-5 min. Move the sonotrode through the mixture to achieve a uniform extraction from all plant particles.
Step 4: After the sonication step, the botanical parts are removed from the flavoured spirit by straining the mixture through a fine filter (e.g. coffee filter, cheesecloth). Repeat the treatment if necessary until all solids are removed.
Step 5 (optional): To create a complex bitters, various bitters are blende together. Different bitter extracts from various raw materials can be prepared on basis of the steps above. A tasteful bitters flavour is obtained from mixing e.g. orange peel bitters with cherry and Entian bitters. Optionally, add sugar or syrup to taste and dilute with water.
Step 6: Finally, the infusion is filled into a clean glass bottle, preferably a glass dropper bottles made from brown glass.
Hielscher’s ultrasonic processors are powerful and reliable, which makes them the ideal tool for the extraction in kitchens, bars and industry. For the small-scale preparation of bitters, we recommend the use of one of our compact lab ultrasonicators. They are handy and user-friendly and therefore very popular for the preparation of bitters in small to mid-size beakers.
For the commercial production of bitters, Hielscher offers a broad range of industrial ultrasonic processors, which can be used for the sonification of batches as well as in continuous flow-through mode.
Contact us today to learn more about our ultrasonic systems and their use in the production of bitters!
Literature / References
- Petigny L., Périno-Issartier S., Wajsman J., Chemat F. (2013): Batch and Continuous Ultrasound Assisted Extraction of Boldo Leaves (Peumus boldus Mol.). International Journal of Molecular Science 14, 2013. 5750-5764.
- Dogan Kubra, P.K. Akman, F. Tornuk(2019): Improvement of Bioavailability of Sage and Mint by Ultrasonic Extraction. International Journal of Life Sciences and Biotechnology, 2019. 2(2): p.122- 135.
- Dent M., Dragović-Uzelac V., Elez Garofulić I., Bosiljkov T., Ježek D., Brnčić M. (2015): Comparison of Conventional and Ultrasound Assisted Extraction Techniques on Mass Fraction of Phenolic Compounds from sage (Salvia officinalis L.). Chem. Biochem. Eng. Q. 29(3), 2015. 475–484.
- Fooladi, Hamed; Mortazavi, Seyyed Ali; Rajaei, Ahmad; Elhami Rad, Amir Hossein; Salar Bashi, Davoud; Savabi Sani Kargar, Samira (2013): Optimize the extraction of phenolic compounds of jujube (Ziziphus Jujube) using ultrasound-assisted extraction method.
Facts Worth Knowing
Historically, bitters have been used as medicinal tonic to ease digestion, regulate appetite and improve vitality. Besides their medicinal qualities, bittering agents from aromatic herbs, roots, bark, or fruits are great to infuse liquids (e.g. alcoholic beverages) with their exceptional flavors. Most commonly used botanicals with bittering compounds are gentian root (Gentiana lutea L., also known as Entian/Enzian), cinchona bark / quinine, cascarilla, cassia, wormwood herb (Artemisia absinthium herba L.), orange peel, and cinchona bark.
Today, two forms of bitters – the digestive bitters and the cocktail bitters – are available and used for different purposes:
The digestive bitters are drinkable liquors, which can be consumed plain or as part of an alcoholic cocktail. popular forms of digestive bitters are amaros and German-style Kräuter liquours, which are mostly consumed as digestif after a meal. Well-known brands are e.g. Averna, Cynar, Ramazzotti, Fernet Branca, Lucano, Montenegro and Unicum.
The cocktail bitters are a common cocktail ingredient used as seasoning in cocktails. They are characterized by a very strong, intense taste so that they are dosed in very small amounts (only drop- or dash-wise added to cocktails). In cocktail bars, bitters are an essential flavouring ingredient, which gives many cocktails their unique flavour note. Cocktails, which involve bitters as an essential component, are e.g. Sazerac, Manhattan, Old Fashioned, Negroni.
Common bitters made from one bittering ingredient are lemon bitters, grapefruit bitters, orange bitters, mint bitters, or peach bitters. Bitters with a complex composition are known as aromatic bitters (e.g. Angostura, Peychaud’s bitters).
Bittering agents can be derived from various plant parts such as roots, tree bark, leaves, blossoms, peels or rhizomes.
Examples for bittering roots are angelica root, barberry root, burdock root, calamus root, dandelion root, devil’s club root, gentian root, licorice root, Oregon grape root, orris root, rhubarb root, sarsaparilla root bark.
Examples for bittering leaves are artichoke leaves, black walnut leaves, dandelion leaves, horehound leaves, mugwort leaves and buds, wintergreen leaves, wormwood leaves.
Examples for bittering barks are cinchona bark, citrus peel, wild cherry bark, quassia bark.
To create complex bitters, aromatic and flavoring agents are added to round out the bitters. These aromatic extracts are from herbs, spices, flowers, fruits, barks, roots or nuts.
Find some aromatic flavouring botanicals below:
Spices: aniseed, artichoke, caraway, cardamom, cassia, celery seed, chili, cinnamon, cloves, coriander, fennel, ginger, juniper berries, nutmeg, peppercorns, star anise.
Herbs & Flowers: arugula, chamomile, daffodil, dandelion, elderflower, hibiscus, hops, lavender, lemon balm, lemongrass, menthol, mint, rhubarb, rose, rosemary, sage, thyme, yarrow.
Fruits: fresh or dried citrus peel such as lemon, lime, orange, grapefruit and dried fruits such as apples, cherries, figs, grapes, pears, raisins.
Nut: almonds, pecans, walnuts.
Beans: cacao beans, cocoa nibs, coffee beans, vanilla beans.