Appearing in the November 1997 Issue of Great Lakes
Fruit Grower News
pastuerization facts need to be put into perspective
Bob Curry of Goodnature Products
such a politically charged word it might be useful to put
a few facts into perspective.
inevitable that pasteurized cider, for better or worse, has
become almost overnight an accepted, and sometimes even preferred
product for the American consumer. The debate over the necessity
or desirability of pasteurization is moot if the market demands
it. While I will continue buying fresh cider for my family
from cider makers I trust, most consumers probably have neither
a personal connection to the cider maker, nor confidence in
their own grasp of food safety issues.
pasteurization is what home canners have been doing to home
grown produce every fall for decades. Those who can apple
cider, are well aware that fresh cider is different from canned
juice that they open in the winter. When canning, the cider
is subjected to high heat (up to 212F) for a long period (15-
30 minutes) of time. Even if the actual heating of the juice
lasts only a few minutes, it takes many minutes for the juice
- when you exceed 175°F (give or take depending on the variety
and condition of the apple) the pectin in the cider denatures
and drops out of suspension. This results in a juice that
is almost clarified on top but has a thick "cloud" of formerly
suspended solids on the bottom. Several national brands of
"natural style" apple juice (After The Fall and Knudsen's)
have this appearance from time to time. Obviously this condition
changes the look, "mouth feel", and taste of the juice and
- to many cider makers - is absolutely undesirable for their
some large industrial juice makers have lately made flash
pasteurization sound like something fresh from the laboratory
and designed specially for juices, it is a process that has,
in truth, been around since at the 1920s with the development
of the first H.T.S.T. (High temperature short residence time),
regenerative plate pasteurizer in England.
pasteurization differs from conventional canning style processing
in several ways.
it takes to rise from ambient to pasteurization temperature
takes several minutes when canning but only a few seconds
in flash pasteurization. A flash pasteurized liquid is held
for only as long as is required to kill a percentage of certain
organisms at a specific temperature. When canning the idea
is to kill all or nearly all spoilage organisms.
case of cider, Cornell University has determined that at 155°
F , 99.999% (a "5 log reduction") of the E. Coli O157:H7 is
killed after six seconds. Since the cider in question is not
going to be treated by the consumer as a shelf-stable product
the other spoilage microorganisms don't have to be killed.
The astute cider maker will probably think the numbers above
are in error. In fact the temperature for a five log reduction
is 155°F for six seconds. Cornell's formal recommendation
included a safety factor of five degrees (160°F for six seconds).
pasteurization implies rapid cooling from treatment temperature
back to some much cooler, condition. Canning, on the contrary,
involves air cooling a mass (whatever is contained in the
jar) to room temperature over an extended period of time.
line is that flash pasteurization is designed to heat liquids,
kill the undesirable organism, and cool the liquid, before
the captive liquid knows what has happened to it. To the degree
you minimize your heat and holding times you will also minimize
degrading your product.
is hoping to demonstrate this concept at the Michigan hort
show by pasteurizing samples of cider brought to the show
by local cider makers. Samples of cider will be available
both before and after pasteurization so that folks can see
that, if done properly, it is nearly impossible to taste the
difference between pasteurized and non pasteurized cider.
difference that is noticeable between raw and pasteurized
cider is the color. The polyphenol oxidase enzyme that changes
the hue of apple cider into a dark brown color is inactivated
by heat. So if you pasteurize right off the press it will
"freeze" the cider at whatever color it is at the time. Thus,
if your cider turns dark over the course of a day, and you
begin pasteurizing immediately after pressing, your cider
will now retain its light fresh pressed color.
- the sublime substance that, more than anything, differentiates
cider from juice, is also what makes pasteurizing cider rather
difficult. As any home canner knows, pectin is what separates
juice from jelly. In the presence of heat, sugar, acid and
water (all items present in the making of jelly and pasteurized
apple cider) pectin is well known for creating jelly. In the
thin gap separating a pasteurizer's heat exchanger plates,
this buildup of jelly is deadly. It is astonishing how quickly
a high tech device like a pasteurizer is brought to its knees
by such an innocuous seeming substance as pectin.
the professor who invented enzymatic depectinization, for
which the first patent was issued back in 1930 (Dr. Peterson
of the New York Agricultural Experimental Station in Geneva
New York) wondered who would even use his discovery - because
he couldn't imagine clarified juice becoming very popular.
How things change in a few short years.
of clarification, in fact, was less for the benefit of the
consumer than for the processor. The few processors who still
pasteurize raw cider (before this year, that is, during which
probably 75 cider mills have begun pasteurizing) all have
to clean their units more frequently and vigorously than when
pasteurizing clear juice so that the pectin does not build
up and affect their process and product. Not only will pectin
gum up a pasteurizer, but it wreaks havoc on any attempt at
apple juice manufacturing today implies that all the lovely
pectin that we value for the mouth feel and health benefits
it contributes to cider (ever wonder what one of the two main
ingredients in Kaopectate is?) is chemically broken down with
synthetic enzymes and then removed so that this pesky pectin
won't get in the way of the processors.
most of the pasteurizers that Goodnature built before this
year were for juice or juice concentrate plants, the added
requirement to counteract the effects of cider pectin were
not completely known even to us. As we developed a line of
small pasteurizers we discovered that the manufacturers of
plate heat exchangers (the plate packs that allow heat to
be transferred from a heating medium to the cider) were not
even aware of the true viscosity of cider or effects of pectin.
They were accustomed to dealing with beer, milk, or depectinized
experience we gained while working with cider producers in
more than 10 mills this summer and fall, we came to the conclusion
that the standard pasteurizer plate is not an ideal design
for pasteurizing cider. Though the standard plate does the
job it is intended to, it is highly susceptible to becoming
coated and even plugged with pectin.
content to be satisfied with the status quo, Dale Wettlaufer,
president of Goodnature, got together with his chief engineer,
Richard Hess, and began redesigning the heat exchanger plates
from the ground up. The idea was to simplify their design
to reduce cost (the plate sets represent the lion's share
of a pasteurizer's cost); and changed the design to make it
more difficult for pectin to build up.
is the Goodnature MFP or Micro Flash Pasteurizer. The cost
for the units is significantly lower than of what a standard
pasteurizer costs without sacrificing any of the standard
safety features. Also, the incidence of fouling from build
up of pectin is significantly reduced.