Hello Pellers, and thanks for a very interesting question.
I enjoyed tackling this for two reasons. One, I love candy, honey,
syrup, ice cream -- anything sugary. Two, I like knowing some of the
details of how the world works. Your question gave me an opportunity
to indulge both a taste for sweets and a thirst for knowledge.
Fortunately for you, the makers of sweet, sugar-based syrupy
concoctions -- from maple syrup to Mrs. Butterworth's -- have been
facing exactly the same problem as you are: How to keep their
sugar-saturated liquid from crystallizing for as long as possible.
From looking through quite a number of sites on this very topic, I can
offer a number of specific recommendations. But first, a few
generalizations:
--There are some tried and true ways of slowing down crystallization.
--Each situation seems to be unique -- something that works for the
ABC Syrup Company might not work over at XYZ Sugar Corp., and it's not
always possible to figure out why.
--Be prepared for some experimentation. It's the only way to pin down
what will work best for you.
Now...on to some specifics.
--------------
I want to start with this site from one of my favorite places in the
world, The Exploratorium, under the Golden Gate Bridge in San
Francisco:
http://www.exploratorium.edu/cooking/candy/sugar.html
The have a section on "The Science of Cooking" which discusses
crystallization of sugar solutions. Although most of the discussion
is focused on the making of candies, the basic concepts, vocabulary,
and tricks of the trade are all applicable to syrupy liquids as well.
(By the way, I can only present a limited amount of excerpts from any
one site -- you should have a look at the links provided to get the
full benefit of the information they have to offer.)
"Why are crystals undesirable in some candy recipes and how do you
stop them from forming?"
"The fact that sugar solidifies into crystals is extremely important
in candy making... Recipe ingredients and procedures for
noncrystalline candies are specifically designed to prevent the
formation of sugar crystals...
One way to prevent the crystallization of sucrose in candy is to make
sure that there are other types of sugar -- usually, fructose and
glucose -- to get in the way. Large crystals of sucrose have a harder
time forming when molecules of fructose and glucose are around...A
simple way to get other types of sugar into the mix is to "invert" the
sucrose (the basic white sugar you know well) by adding an acid to the
recipe. Acids such as lemon juice or cream of tartar cause sucrose to
break up (or invert) into its two simpler components, fructose and
glucose. Another way is to add a nonsucrose sugar, such as corn syrup,
which is mainly glucose...
Fats in candy serve a similar purpose. Fatty ingredients such as
butter help interfere with crystallization--again, by getting in the
way of the sucrose molecules that are trying to lock together into
crystals....
-----------------
So you can see here two strategies for preventing (or at least slowing
down) crystallization, both involving adding something to your
product. One, is adding any material causing the sugar to invert.
The other is add ingredients -- other sugars or fats -- that also
inhibit crystal formation.
-----------------
Another site has a similar discussion about what causes
crystallization -- and how to prevent it -- and focuses on one of my
all time favorites, maple syrup:
http://ohioline.osu.edu/b856/b856_47.html
North American Maple Syrup Producers Manual
There's a lot at the site about "invert sugars" and "supersaturation"
and the like...I won't repeat most of it here. But there's one
segment in particular I do want to bring to your attention, since it
has a "recipe" for inverting maple syrup sugars:
"... the additive solution can be prepared as follows: To 1 gallon of
standard-density maple syrup add 2 1/2 liquid ounces of invertase (an
enzyme that causes the conversion of sucrose to invert sugar). Stir
the mixture thoroughly and allow it to stand at room temperature (65
degrees F or above) for several days. During this time sufficient
invert sugar will form so that 1 pint of this solution can be used to
adjust 6 gallons of maple syrup low in invert sugar. Invertase may be
purchased from many confection manufacturers."
"Another convenient type of additive is an acid salt such as cream of
tartar (potassium acid tartrate). Addition of 1/2 teaspoon of cream of
tartar to 1 gallon of low-invert syrup just before it is boiled for
candy making will cause sufficient acid hydrolysis or inversion of the
sucrose to form the desired amount of invert sugar."
-----------------
Here, then, are two more additive possibilities: invertase and cream
or tartar. Cream of tartar can be found in just about any
supermarket. Invertase is more of a specialty item, but can be found
in kitchen/food service supply houses fairly readily. For instance,
this site:
http://www.kitchenkrafts.com/product.asp?product=IN0103
offers Invertase in 1 oz. jars for $3.25
"Used to make smoother fondant and cordial centers. Natural enzyme
derived from yeast converts sugar (sucrose) to invert sugar, thereby
preventing crystallization..."
while this site is pretty much all invertase, all the time:
http://www.invertase.net/
and sells the stuff in 1, 10 and 44 pound containers.
The site also has links to information about purchasing invert sugars
directly...you can skip the step of forming inverts by adding
invertase, and just use "off the shelf" inverted sugars as an
additive. The information is a bit on the technical side, but is
worth plowing through if you want to give the invert sugars a try:
http://www.britishsugar.co.uk/bsweb/sfi/pages/invert.htm
----------------
Another substance prone to the same problems of unwanted crystal
formation is honey, and this site addresses the issue head on:
www.nhb.org/download/factsht/crystal.pdf
Honey Crystallization
"Can crystallization be avoided?"
Again, the entire site is worth reading, but I just want to excerpt
here a few key anti-crystal strategies:
"Spontaneous crystallization is controlled primarily through proper
storage, heating and/or
filtering."
"Holding honey at temperatures in the range of 104--140 °F during
bottling also slows the rate of crystallization."
"Filtering removes particles that can act as nuclei that might
initiate crystallization."
"The crystallization process can be avoided with proper storage, with
emphasis on proper
storage temperature. For long-term storage, the use of air-tight,
moisture-resistant
stainless steel drums is recommended."
"Cool temperatures [below 50 °F...] are ideal for preventing
crystallization. Moderate
temperatures [50--70 °F...] generally encourage crystallization. Warm
temperatures [70--
81 °F...] discourage crystallization..."
"During storage, low-density polyethylene containers can allow
moisture to escape, which may contribute to the crystallization
process."
-----------------
So now we've added several other strategies for extending storage
life:
--hot filling during bottling or containerization.
--filtering the product to remove particles (any particle present
helps initiate crystallization)
--appropriate selection of container materials -- glass or steel is
better than plastic, but if plastic is essential, high-density is
better than low-density.
--storage at moderate temperature is least desirable; either cool or
warm is preferable.
-----------------
I want to stop here and summarize what I have at this point, and then
post it as an answer. This way, if you need any additional
information, there will be time for a round or two of clarifications,
before you get to your deadline on June 5th. Keep in mind -- the
process isn't over until you're satisfied with the response.
Now, to recap:
--Ingredients. You have a wide choice of substances that can be added
to prolong the shelf life of your sugar solution. Invertase -- or
direct addition of inverted sugars -- is a very widely used practice
in the food industry. Other materials -- acids, fats, proteins --
will also minimze crystallization. It will take some experimentation
to hit on the best quantities and procedures, but the maple syrup
"recipes" for invertase and cream or tartar should serve as a good
guide.
--Work clean. Minimize any dust or other particles that can get into
your materials. Consider filtering the product batch as it is being
put into bottles or containers.
--Material selection. Non-porous is best, and this means glass or
metal containers, although high-density plastics are also a viable
packaging option.
--Temperature control. Hot containerization is recommended. Cool
storage may be the most practical option, but warm storage is also
effective at slowing crystallization.
I hope this is helpful. If you find you'd like additional
information, I'd be happy to provide it, and will do my best to get it
to you as quickly as possible. Just let me know through a Reqeust for
Clarification what you need (and remember to provide me as much
additional detail as you can regarding your production circumstances.)
Good luck with your venture.
pafalafa-ga
Search strategy: Google searches on a variety of combinations of:
sugar solution supersaturated invertase prevent crystallization |
Clarification of Answer by
pafalafa-ga
on
05 Jun 2003 08:12 PDT
Pellers,
Glad to hear that we're on the right track with the information I've
provided. Here's some additional information that I hope will be just
as useful -- I've tried to get it to you as quickly as possible, given
your tight deadline. I will address the topics you raised one by one,
and then I want to make a suggestion that can address the whole ball
of wax at once.
Additives -- all the additives I mentioned in my original answer are
food-grade, and can be added to your sugar solution. Of these, corn
syrup might be one of your best options -- it is used very commonly as
an anti-crystallization agent, and it is already a well-known and
familiar sweetener, so that it shouldn't have much of an impact on
flavor.
Packaging -- From what I've learned so far, the packaging options you
have under consideration (satchets or coffee shop style containers)
should be acceptable for what you have in mind. The keys are: (1)
smoothness (rough surfaces promote crystal formation) so plastic or
metal is preferable to paper products, and (2) moisture retention, so
I would steer clear of the very light-weight plastic satchets that are
sometimes used, in preference for the aluminized ones, or high-density
plastic containers. As far as I can see, there are no specialty
coatings in common use that are specifically meant to inhibit crystal
formation.
Storage -- As I noted earlier, either refrigeration OR warm-storage
can minimize crystallization. However, storage for 12 or more months
seems to be "pushing the envelope". For instance, here are the storage
recommendations for one brand of corn syrup:
http://www.cargillfoods.com/products/product_sweeteners.html
Storage and Handling
The recommended storage temperature range for IsoClearŪ 55% High
Fructose Corn Syrup is 80 - 90°F. Syrups stored for extended periods
(over 6 months) should be evaluated periodically for fitness of use.
[Note that they suggest warm storage as the best option]
-------------
Obviously, you have a challenging situation in front of you.
Here is the overall recommendation that I want to offer. Your project
requires a level of professional, technical expertise that goes beyond
what can be offered through a service such as Google Answers.
Such expertise can be available at no initial cost to you, as long as
you bear in mind that the experts you will be consulting have a
product to sell, and may not be inclined to offer information on
solutions that they don't, themselves, sell.
With that in mind though....
Cargill is one of the world's leading suppliers of corn syrup, and
promotes it as an anti-crystallization food-grade additive. They have
a "Solutions" page, where you can email the company with questions
about food preparation, storage, packaging, additives, etc. They can
obviously provide far more technical expertise than I can. You may
want to contact them about your particular set of questions:
http://www.cargillfoods.com/solutions/food_applications.html
"Cargill's vast food application resources are available to help you
explore new products and market opportunities. As a world leader with
experience across many ingredients and industries, we have an
accumulated knowledge base you can draw on to create exciting new
products, add value to existing ones, and bring your ideas to market
quickly."
----------------
And again, I hope this meets your needs in a timely fashion. Best of
luck in your enterprise.
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