Glycerine, Glycerites and Preservative Power

A lot of you lovely readers have been inspired by the glycerites I have been making lately, and several of you have asked me about the preservative power of glycerine.

Can glycerine function as a stand-alone preservative in a glycerite?

This is an excellent question.


Because the answer is not as straightforward as you were undoubtedly hoping it was going to be, but stick with me and we'll take a serious look at the hows and whys of glycerites and the preservative power of glycerine.

Preservatives in Glycerites? Is that Even Necessary?

The need for adding preservative to a glycerite depends. It depends not only on what you are using to make your glycerine extract, but on how much you use of what.

You: (groan) Really, Lise? Seriously? Does this have to be so difficult from the get-go?! Surely there is a simple answer!

I feel your frustration.

But you have to remember that glycerites can be made with a gazillion (if not a trillion gazillion) different things:
  • dried herbs
  • fresh herbs 
  • dried whole flowers or petals
  • fresh flowers or petals
  • dried fruits
  • fresh fruits 
  • fresh veggies 
  • etc.
So there's really not one perfect answer to this question. I wish there was, but then life would just be far too simple, and life – apparently – doesn't like being simple when it comes to glycerites.

Why Life Isn't Simple When it Comes to Glycerites

While researching glycerite-making methods, I came across numerous different recommendations of how much glycerine to use to ensure proper preservation.

And all this time, I did not come across a single written or online source that could recommend percentages when making a glycerite with fresh food.

Not.  A.  Single.  One.

I did make note of every recommendation did find. And according to those recommendations, each of the following percentages is the norm for how much glycerine to add to a glycerite:
  • over 25%
  • 50%
  • minimum 50%
  • over 55%
  • 75%
  • 80%
Quite a span, there, don't you agree? Many of these sources also offered a 'use by' period, and the range was from 6 months to 2 years.

These sources all struck me as serious, professional, and experienced.

My first post on cucumber glycerine extract (link below) referred to a guide that called for 50% glycerine, reconstituted dried herbs and the addition of 0.6% broad spectrum preservative.

I chose to (almost) follow that guide with the fresh food glycerites I have been making – using 0,5% preservative and a glycerine percentage of 'just around 50%'.

'Just around 50%'? Is That Accurate Enough?


'Just around 50%' is not accurate enough.

With fresh fruit and veg, the water-to-glycerine ratio gets tricky. To add to the fun, fruits and many vegetables contain sugars – which can make for an additional challenge.

If you don't know the exact water (and sugar) content, it's pretty much impossible to calculate exact percentages.

How does one measure the exact water (and sugar) content of a fresh strawberry?

One cannot (if one also wishes to use it in a glycerite).

The only way to approach the water question is to find the average water content of said fruit (or veg), then work from there.

But average numbers are not exact numbers.


To know for absolute sure how much – if any – preservative needs to be added to any glycerite, you need to do some calculating.

For Real?!!

You: (groaning and eye rolling)  Math, Lise?! Seriously?! Could this get any worse? Why isn't there an easier way?

I totally feel your pain.


I've already spent quite a bit of time trying to find the answers. And if there was an easy, all-in-one, simple-dimple answer to this question, I would hand it to you on a silver platter.

But there isn't.

So I can't.

But there's something I can (and will) do.

What I Can Do

I can give you a general guideline, and that is this:
Glycerine will greatly reduce the possibility for bacterial growth when it exceeds 50% percent of the formula.

You still have to do the calculating on the material you are using and go from there.

Because here's the thing:
from what I have been able to find in the time I have been researching this, it would appear that information on the preservation power of glycerine in fresh food glycerites is completely uncharted territory.

In short: your guess on formulating the perfect glycerite is as good as mine.

I can (and will) also give you a few helpful tips to help you on your way.

 A Few Glycerite Making Tips

  • Always measure accurately – and by weight 
  • Always work clean (keep your work space clean, sterilize equipment, etc) 
  • Keep copious notes
  • Label everything you make with a date, ingredients, and everything else that will help you recreate (or be able to pinpoint why you don't want to recreate) your 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 will require a bit of storage space as you continue to make products).
  • Keep even more notes 
It won't be long before you have your own encyclopedia of experience and notes to draw on.

Have fun.

Even with the math part.

You can totally do this. How do I know? Cuz I just know.


Do Tell

How long do your glycerites last? Please share by dropping a comment!


John Kabara, Donald S Orth, Preservative free and self preserving cosmetics and drugs, Priciple and Practice, 1996, 45-69

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, 160

Gladstar, Rosemary, Family Herbal  Guide to living life with energy, health and vitality, 2001

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 


María said…
Well, talking from my own experience, it's not the same thing speaking about the glycerite itself or the whole formula.
The glycerite may preserve itself when the amount of glycerine is 25% and above. By the osmose principle, bacteria may not live in such environment. In addition, glycerine is an alcohol: glycerol, which adds antiseptic properties.
However, the whole formula has to be preserved as usual.
I don't think, and I reiterate it's only my opinion, that the usage of a glycerite in a formula changes a lot the preservation, as the glycerite is just another ingredient, another active.
But yes, we need to do the math. I love to keep things simple so I tend to make 50% concentration glycerites.
LisaLise said…
As always, your input is great! Thank you - and I agree -- keeping things as simple as possible is ideal
María said…
This comment has been removed by the author.
María said…
I don't know why my comment is repeated. I'll delete (if I can...)
LisaLise said…
sometimes the commenting on Blogger goes wonky in different ways -- maybe they're updating something at the moment
Celina said…
I just made a Mulberry glycerite to include it in my skincare formulations and loved it. Now I would like to make one with red algae which I have available in my area.
Can I make a glycerite with algae? Fresh or dry form? Have you any tips on this one?
I wish you a blessed year 2019!

LisaLise said…
Hi Celina - I would imagine you could make quite a lovely glycerite with both fresh or dry red algae. If you have my book, you'll find calculation charts for dry and fresh materials.
TheSoapGallery said…
Hi! So I tried making a glycerite with strawberries and I used a preservative (geogard ect) @ 1%, and kept it refrigerated. Unfortunately it lasted only 3 weeks before I saw visible mold and had to throw it out.
Should I had added more glycerine, you think?
LisaLise said…
Hi TheSoapGallery - Without knowing more about your raw materials, percentages and process it's really hard to give you an answer as to why your mixture grew mould.
A few initial questions come to mind, that might help you pinpoint the problem:
1. If you used fresh strawberries, did you use prime, undamaged and fresh examples? Do you know if they were free of pesticides?
2. Did you rinse them (in distilled water) and allow to dry before adding them to your glycerine?
3. If you used frozen (or dried or freeze dried) strawberries, were they completely free of additives (sugar, colorants, etc)?
4. Was the container and lid properly sanitized before use?
5. Was your workspace, tools and equipment clean?

As to your preservative, this should most definitely work as it is a blend that offers broad spectrum preservation. There is one thing a preservative cannot do, and that is make a contaminated product fresh, so my initial thought is that your raw materials might be the culprit in this case. I admittedly get real up close and personal with every piece of fruit I add to a glycerite - check from every angle, pull out a magnifier if anything looks even slightly dodgy and discard any material that doesn't pass muster. It's a bit time consuming, but I find worth the time and effort it takes to examine every little bit of fruit I use.
Unknown said…
Hi Lisa,
Thanks for such a lovely post. I just added few fresh Blue pea flower petals in glycerine for 10 days now. Do I need to add preservative to it or no need as there is no water and it is 100% glycerine. If i have to add preservative, which one to use and what is the percentage. Please help me. Thanks
LisaLise said…
Hi Unknown - Thanks for your kind words. Not knowing your proportions of everything it is impossible for me to answer. If you visit and check the shop, you'll find my a book about making your own glycerine extracts: The Art of Making Glycerites for Cosmetics. It shows you how to make self preserving as well as glycerites with added preservative. There's a complete description of the contents so you can get an idea of what's included. :)
Marcela said…
Hi Lisa, first of all thank you for such good posts, love the way that you transmit your knowledge.
I'm a beginner formulator and wish to start my journey thru glycerite. Have some big doubt about glycerites made with dry herbs and flowers. First do I need to introduce water? And if is needed (even being dry matter) do I need preserve?
I my researches I never found one indication for use of the preservative in that case. What is a bit confusing for me because they all used water at the formulations.
Another question it is permitted the use of fresh fruits and vegetables in glycerite for skin care? It's seams so difficult to keep the product safe and with a standard of colour and nutrients...
Thank you so much in advance!!! Hope I made my self clear :)
LisaLise said…
Hi Marcela - Thanks for your comment. My book, The Art of Making Glycerites for Cosmetics answers all of your questions (and more). If you visit the shop on at there is a pretty detailed description of what the book includes.
Unknown said…
Hi, I've just come from watching the videos you did with Marie from Humblebeeandme and of course it lead me to reading your blog. I'm from the Caribbean and it's mango season. As your book is out of reach for me at the moment, can you tell me if you've made a mango glycerite and would the ratio 30% mango to 70% glycerin be safe to start with? Thanks
LisaLise said…
HI There and thanks for popping in! Your mango glycerite idea sounds lovely and you can get detailed instructions for doing fresh food glyceriites in my book (which is an e-book and delivered immediately upon purchase). If you want to read more about it click the picture at the bottom of this post.

As for your percentages of raw material to glycerine, this could work well – remember to observe proper GMP (Good manufacturing practice) :)