My work with fresh food glycerites came about because of an interesting question from a reader: Why can’t we formulate with fresh food?
Although it is technically possible to preserve and use some fresh foods in cosmetics (links below), it is generally neither viable nor practical.
Enter glycerites: extracts using glycerine as the main extraction medium. Traditionally, these are made by adding fresh or dried plant material and water to glycerine, letting the mixture sit for a period of time (with daily agitation), then straining and bottling.
It is also entirely possible to make glycerites using fresh fruits and vegetables. The fresh-food glycerites I have made to date have all demonstrated a wonderful ability to not only capture, but to retain the scent of the food.
A splash of strawberry glycerite in a skin tonic adds an extra dimension of natural freshness that is positively addictive!
Glycerine Has Multiple Functions
Glycerine can be from both animal and vegetable sources. Vegetable glycerine is most often soy, palm or coconut based and has a slightly higher water content than the non-plant version – commonly made from animal tallow.
In skincare, glycerine functions as a humectant – drawing moisture to the skin when it comprises under a certain percentage of a formula (generally recommended at 5% – 10%).
However, at higher percentages, glycerine can do quite the opposite – drawing moisture from the skin.
Dosage is everything when it comes to glycerine – because it has another really cool and useful ability: it can function as a preservative or aid to a preservative.
Glycerine and Preserving Power
Since glycerine can function as a preservative all by itself, one would think it completely unnecessary to add a preservative to a glycerite.
This is something I am (still) researching and testing, but at the time of writing this, the best answer I can offer is: it depends – not only on what you are putting into your glycerite, but also on how much you use of what.
It would be wonderful if this were all a bit simpler, but then life would be too simple and apparently, life doesn’t like being simple – particularly when it comes to glycerites.
It may be because glycerites can be made with everything from dried herbs to fresh flower petals that there are so many different guidelines available. According to the numerous sources I have found, a properly preserved glycerite can be achieved using any of the following percentages of glycerine:
– over 25%
– minimum 50%
– over 55%
Which one is correct?
As if this wasn’t enough, there are some who recommend adding preservative. In March, I did a blog post on cucumber glycerite (link below). It referred to a guide that called for:
0.6% broad spectrum preservative
Why add preservative? Perhaps because there doesn’t seem to be any consensus on how much glycerine to takes to function as a stand-alone preservative in a glycerite. Or perhaps it has to do with the water to glycerine ratio.
Ratios and Percentages
In a glycerite with dried herbs, it is easy to be accurate about total water content because the water is weighed out and added. In a glycerite using fresh plants, it becomes a bit trickier, although there seems to be a general consensus of using minimum 55% glycerine.
With fresh fruit or veg, the water-to-glycerine ratio gets pretty darn tricky to figure – and if the water content is ‘a guesstimate’, it’s impossible to calculate exact percentages.
How does one measure the exact water content of a fresh strawberry?
The only way to approach this is by finding the average water content of said fruit (or veg), then working from there. But average numbers are not exact numbers, so to know for sure how much – if any – preservative needs to be added to a fresh food glycerite, some serious calculating is involved.
To make things even more complicated: most fruits and vegetables have a natural content of sugar which should be factored in as well. The ‘right’ amount of sugar in a glycerite could create ideal conditions for a bacteria rave party.
During these past months of glycerite-making and glycerine research, I have not come across a single site or written source for recommended glycerine percentage with fresh-food glycerites. It would appear that makers of fresh-food glycerites are sailing in unchartered waters.
And that kind of makes it all a little exciting, don’t you think?
Summary for preserving Glycerites
- There seems to be a general consensus that glycerine functions as an adequate bacteria inhibitor when it EXCEEDS 55% percent of a glycerite with dried herbs.
- There doesn’t seem to be any general consensus on the amount of glycerine to add if it is to function as a stand-alone preservative in glycerites with fresh herbs.
- The author has been unable to find any information on the amount of glycerine to add for fresh-food glycerites.
Fresh Food Glycerites: LisaLise’s Tips
- Never let unchartered waters deter you from making glycerites with fresh foods – there’s a world of undiscovered delights to be had!
- Choose foods that are at the peak of their freshness (or ones that you just love the scent of)
- Choose foods rich in water-soluble actives
- Be meticulous about cleanliness – both in preparation of the food and your workspace
- Ensure you are using food with an untreated surface
- Peel any fruits or vegetables that may have a treated surface
- Always measure everything by weight
- Always measure accurately
- Use sterile containers
- Straining any glycerite is an exercise in patience (expect 3-5 hours for approx. 250ml of product depending on the food used). Therefore, it’s an excellent idea to prepare a place where your glycerite can do its thing where there is no risk of dust, bugs, or any other unwanted bits and pieces gaining access (a large, loose ’tent’ of foil placed over the entire setup works very well for me).
- Keep copious notes (note from the Formula Botanica team: use your skincare formulation journal!)
- Label everything you make with a date, ingredients, and everything else that can help you recreate (or be able to pinpoint why you don’t want to recreate) this particular formula
- Always save a LABELLED, DATED portion of your formula for observation – even long past your ‘use by’ date. This is by far one of the most educational things you can do for yourself and can easily be applied to everything you make. (It will also require extra storage space as you continue to make products)
- Keep even more notes, because in absolutely no time at all, you will have your own encyclopedia of experience and notes to draw on.
Glycerites: Infusion Time
- Average for fresh food glycerites: 5-7 days
- Average for dried food glycerites: you tell me – I haven’t tried this yet
- Average for dried herb glycerites: 7-14 days
- Average for fresh herb glycerites: 6-10 days
Have you ever made a glycerite? What are your experiences? Leave us a comment below!
- Jay E. Slater, MD, The role of glycerol on allergen extracts, Laboratory of Immunobiochemistry, FDA
- Rebecca Wright, Guide to preserving Natural Products
- John Kabara, Donald S Orth, Preservative free and self preserving cosmetics and drugs, Principle and Practice, 1996, p45-69
- Preserving Syrups, The Pharmaceutic and Compunding Laboratory, UNC Eshelman School of Pharmacy
- Cech, Richo, Making Plant Medicine, 2000
- Gladstar, Rosemary, Medicinal Herbs: A beginners Guide, Lemon Balm Glycerite, p160
- Gladstar, Rosemary, Family Herbal: Guide to living life with energy, health and vitality, 2001
- Wikipedia, Glycerine
- Green, James, The Herbal Medicine Maker’s Handbook – A Home Manual, p 185-192
- Wynn, Susan, Fougere, Barbara, Veterinary Herbal Medicine, p225
- Fetro, Charles W, Avila, Juan R, The Complete Guide to Herbal Medicine, p8
- Preservative for Biological Specimens, US Patent, 1978
- Soap and Detergent Association, Glycerine, on overview, 1990
Links to LisaLise Blogposts Related to This Article
- Formulating with food – is that even doable?
- Formulating with food Part 2
- Cucumber Glycerite – part 1
- Cucumber Glycerite – part 2 – straining
- Strawberry Glycerite
- Lemon Glycerite
- Blueberry Glycerite
Lise M Andersen is a 100% self-taught creator and producer of hand-crafted plant-based cosmetics. Her cosmetics-making journey started in her teens with a how-to book.
Based in Copenhagen Denmark, Lise is bilingual and answers to both the English and Scandinavian versions of her name: ‘Lisa’ and ‘Lise’ – the basis for her company name.
Lise makes formulas under the mantra “less is more, but let’s not sacrifice function or forget the all-important luxury factor.”
Her website, LisaLise.com offers bespoke cosmetics, custom formulations and a web-shop with made to order and beginner-friendly DIY kits.
Lise is constantly researching ingredients and documents her product development and shares numerous How-To’s on her blog: LisaLiseBlog.
Earlier this year, she started Formulators Kitchen – a free, wiki-style online community for formulators that includes a forum, common resource area and even a formula-sharing database. Access is by invitation only, but new members are welcome. Check the post in Formula Botanica’s free Facebook group for details, or contact firstname.lastname@example.org for an invitation.
All photos were kindly provided for this blog post by LisaLise.
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Lorraine Dallmeier is a Biologist, Environmental Scientist and the Director of Formula Botanica, the award-winning online organic cosmetic science school. Read more about Lorraine and the Formula Botanica Team.