Welcome back for another edition of Ask The Formulator! Today, let’s talk about shelf life. It’s a topic of interest that seems to bring confusion to many. Since there are several questions I’ve received on this topic (Thank you for asking, btw.), I’m going to address the main ones in one post today because they all tie in together.
Question#1: Is shelf life really important and are these “dates” reliable?
Answer: Yes, the general shelf life of both individual ingredients and finished products hold some importance. They give us an idea of the expected life span of an ingredient or finished product and how long the product or ingredient should be safe and uncompromised under advised or normal conditions. But….and this is a BIG BUT…..the shelf life given for a product or ingredient is not set in stone. In fact, you will find varied numbers given over multiple resources. “Shelf life” is actually a relatively ambiguous term in the grand scheme of things. Many see the “shelf life” of cosmetics or any other product as a “use by” or “expiration date”. While there is some truth to that being the case, it’s not really an “always” situation. The shelf life gives us an idea of how long an ingredient or finished product should be viable and stable. However, it’s merely a rough estimate based on normal expectations which are based on various factors and considerations. In other words, it’s not a hard and fast rule but rather a general rule of thumb….a guideline based on known factors and expectations.
Many different factors can play a very large role in how long an ingredient or finished product is stable and viable and when it should be tossed out. With raw ingredients, an application of science and experience is used to determine estimated shelf life. However, it’s conditional on handling and storage just like with those strawberries or that flour you have in your kitchen. With professionally formulated and manufactured products, actual testing needs to be done in a lab and over a few years to determine efficacy, stability and the shelf life we can expect under normal circumstances. This testing gives the manufacturer a good baseline expectation of the shelf life of the product. But this too is conditional. Truth is, no one can predict when a fixed oil will oxidize/become rancid, when an ingredient will go bad or when a product has reached the end of its life span. It’s all wrapped up in educated guesses and known information to come up with the best case scenario.
Question#2: Does the shelf life mean when I buy an ingredient or product, if I don’t use it all before the stated shelf life date, it’s bad and I need to throw it away?
Answer: Well, the answer to that is “Maybe”. Let’s look at the often used ingredient, shea butter, for example. Most of the information you find gives shea butter a shelf life of 12 to 24 months. But guess what? I have personally had shea butter that became rancid/oxidized at around the 6 months mark after I received it, even though I stored it properly in a cool, dark place, kept air out of the container and did everything right. Why did it need the be trashed in just 6 months when the shelf life is much more than that?
For starters, the shelf life for raw ingredients or finished products doesn’t begin when a customer receives it. It starts at time of manufacturing. So if an ingredient, such as shea butter, sits in a warehouse for months before it is shipped to the end customer, it’s already lived part of the estimated lifespan. This is why we want batch numbers and use by/expiration dates on the packaging. And why we should know how that date is determined. Most suppliers purchase raw ingredients in huge bulk then transfer it to their own branded packaging for retail or wholesale. If the ingredient has an expiration/use by date on the label, it will not usually be the actual date when the shelf life began. When does the shelf life begin for raw ingredients? When ingredient was extracted and/or processed. The manufacturer may not know the extraction or processing date and they may not receive an ingredient to repackage until several months after it’s actually processed/manufactured. Most suppliers use the date THEY receive and/or package it, not the date the ingredients were processed at the source. So we need to account for that discrepancy and keep it in mind.
Another reason is we have no idea how the ingredient has been handled and stored or if it’s endured temperature fluctuations, air exposure, etc. at any time before we receive it. These effect the stability and shelf life as a whole. I’ve had shea butter still be good a few months after the given shelf life or use by date. Why? My best guess is it was very fresh when I received it, had been properly handled before it reached me and I treated it well to make the most of my investment, thus prolonging the shelf life.
Question #3: How do I know what the shelf life is when I make something like lip balm or whipped butter, for example? Is there a way I can determine the shelf life of a product with certainty?
Answer: With finished products, it can be quite difficult to determine a relatively accurate shelf life of the product. There are multiple ingredients, each with their own estimated lifespan and remember, we don’t know the actual date of when the lifespan began. Determining shelf life can be especially hard for the home-crafting DIY enthusiast because in most cases, they don’t have the knowledge or experience to pull from. But it’s not limited to the home-crafter. Many who sell products don’t really know how to determine shelf life of a finished product or take the measures needed to make a more educated and reliable assessment either. Some take the easy route and just go with the estimated shelf life they find for the ingredient with the shortest life. Others will just take a conservative or liberal guess based on whatever parameters they deem important. Still others will basically pull a timeline out of a hat for marketing appeal or quicker repeat sale turnover. Some don’t bother with it at all. Then others, dedicated and ethical professionals like myself, will put the product to the test (literally) and compile various points and facts about the product before they attach an estimated shelf life or use by date. This includes the estimated shelf life of each ingredient, the formulation as a whole, preservation factors, the possible or likely conditions of use and storage by the end-user, their experience and other considerations. We’ll try to give a reasonable but somewhat conservative number based on what we know to be true. But it is in no way a guarantee and is 100% conditional on the end-user and how they handle and use it. Once it leaves our hands, it really is out of our hands.
As an example: When I’m asked “What’s the shelf life of your lotion?”, I will tell you my tests and experience have shown when stored and used as expected, it will be stable and safe for up to 24 months from time of manufacturing, but I recommend you use it up before then, maybe by 12 months or so. Does that mean if you purchase a bottle today, I make it tomorrow and ship it out to you in a few days, that in April 2018, I’m advising you to throw it out? Or if you still have it come April 2019, you must toss it in the trash? Not at all. It means I have tested the formulation at various timeline intervals from date of manufacturing to two years from that date. Those tests have shown me when it’s properly stored and handled, the lotion still remained stable with no separation of emulsion, had not changed in consistency or texture, the fragrance (if scented) was still good and it showed no microbial growth at the two-year mark. So I can estimate the “shelf life” to be approximately 24 months but I recommend you use it up sooner, in about one year or so. However, it could be less or it could be more, depending on various factors including where and how it’s stored, if it’s exposed to excessive or repeated temperature changes or extremes, has it been exposed to air repeatedly, has the pump been taken in and out a few times or a dispensing cap been left off, has anything been added to it (please don’t do this), has it sat unused for a while after it is received, etc. BTW, I haven’t tested beyond 24 months because who keeps a lotion that long? I usually use a bottle up in about 6 – 8 months max myself. So our lotions could feasible last longer if well cared for. I just don’t know that for a fact.
So, as you can see, the shelf life of ingredients and finished products is important but it’s not a precise science. It’s mostly educated guesswork and estimations, dependent upon the multitude of variables involved and is neither set in stone or a guarantee. Sounds a lot like life in general, huh? I hope this helps you understand shelf life a bit better and encourages you to treat your products and individual ingredients with the up-most care to protect your investment as best you can. You also need to resolve yourself to the fact you need to discard when necessary. Seriously, don’t be a thrill seeker when it comes to this. You may find yourself throwing away products or ingredients sooner than you wanted to but in the end, it will help insure you do not use unstable or compromised products.
I hope this helps you understand shelf life a little better. Who knew there was more to it than meets the eye? Well, now you do.
Y’all send me your questions, will ya’? I will try to answer them if I can. While I may not be able to answer every question, I’ll do my best to guide you where to research yourself or perhaps find the answer for you. My main desire is for you to be informed, not influenced, and able to make choices that are right for you and your family based on truth and reasonable expectations, not misinformation, fear or inflated promises. OK, that’s all for today.
Until next time, enjoy the Ahhh moments, y’all!