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Finding Toxin-Free Coffee: What to Look For.
“Is your coffee toxin-free coffee?”
This is the question I have been asked many times by other healthcare professionals/ coffee enthusiasts over the last few months. I found it to be an interesting question, worthy of research so I decided to use my resources so we can see if there is any validity to the question.
Is there really a valid health concern about toxin levels in coffee based on the current research at hand?
Let’s start by learning what toxin we are addressing in realm of coffee.
Ochratoxin A (OTA)
To answer this question we will need a little background…
The toxin most people are concerned about is Ochratoxin A. It is naturally present in many crop products, such as cereals, coffee beans, cocoa and dried fruit. The tolerable weekly intake (TWI) of Ochratoxin A is 120 ng/kg body weight.2
Ochratoxin belongs to the overall category called Myotoxins, which are secondary metabolites produced by mold, which can be taken in through eating and drinking. Despite attempts to rid our food of these toxins still are present in most foods. Currently, the U.S. has no standards for OTA levels in coffee as some other countries do.
What does mold need to grow in coffee?
Mold, just like any other organism on earth, needs a few things to grow. Mold needs water, oxygen, and an ideal temperature (~40 – 100 degrees F). In tropical climates, water can be attained through high humidity and oxygen is more abundant at lower elevations.
The elevation is an important variable in choosing a toxin-free coffee. Coffee is grown at low elevations (under 2,500 ft. or 762m), high elevations (under 5,000 ft. or 1,500m), and everywhere in between. Higher elevations have less oxygen, which is why it is harder to breath in the mountains than at sea level. Lack of oxygen in the higher elevation will slow mold growth.
Also the presence of caffeine has been shown inhibits mold growth. As little as 2mg/ml in the area of the mold has been found to completely inhibited mold growth in some studies.1 If you’re concerned about mold and toxins, perhaps you should not drink decaf coffees.
How to Process an OTA toxin-free coffee on the coffee farm
The way in which coffee is grown, harvested, stored, and processed all have an effect on the amount of toxins entering your cup. Even the elevation at which a coffee plant is grown has an effect. How a coffee bean is processed, or de-pulped and prepped for drying, is a simple thing to ask a coffee seller.
There are three types of processing of a coffee cherry: wet, dry and semi-dry. Wet processing is known as the more “toxin free” way to process a coffee bean. Dry, also called unwashed or natural coffee, is the more traditional way. Semi- dry is also called wet-hulled, semi-washed, pulped natural or Indonesia Giling Basah.
Dry Processing:
Let’s start with a short description of dry processing since we will focus majority of our attention on wet processing. Dry processing is where the coffee cherry (pulp and all) is left in the sun to dry for around 4 weeks. Just think of a piece of fruit being dried in the sun for weeks. Exposure of the coffee cherry pulp to the environment presents a good chance for mold to grow. Mold produces Ochratoxin A and leaves it sitting on the skin of the coffee bean after the pulp is removed. Interestingly, I have heard dry processing produces more flavorful coffee, as the fruit is actually drying around the coffee bean, allowing for saturation of the flavors.
Here is a list of some coffees often subjected to dry processing due to high humidity or frequent rain during coffee harvesting season.
Brazil Arabica coffee beans
Ethiopia Arabica coffee beans
Haiti Arabica coffee beans
Paraguay Arabica coffee beans
Most Robusta coffee is dry processed. Robusta is the opposite of Arabica coffee beans and if you buy Arabica coffee beans, like most of the U.S., don’t worry about Robusta.
Wet Processing:
Wet processing, also called wet processed or washed coffee, is where the fruit of the cherry is removed before drying the coffee beans; it requires a large amount of water hence called “wet processing.” The pulp is mechanically removed and any remaining pulp is taken away with fermentation or mechanical scrubbing. During wet processing the mucilage layer (the thick glue-like substance produced by plants) is removed during the 24 – 36 hour fermentation step. This removal of the mucilage layer is a major difference between wet and semi-dry processing.
Again the mucilage can be removed via fermentation or mechanical scrubbing (also know as machine assisted wet processing). Mechanical scrubbing has been used to help decrease water usage (pollution) in processing but it’s important to note fermentation also a quality control method, allowing better coffee to reach your cup.
Remember we want to decrease mold since it is the producer of the harmful toxins. Allowing coffee to have mold during processing would yield a high level of Ochratoxin A in your morning cup. Possible mold is minimized with near complete removal of the moist cherry pulp before the coffee beans are left to dry in the sun. As we all know, mold grow is wet, dark places… a moist cherry (left for weeks) would be a great place for mold to grow.
Semi-dry Processing:
Let’s not spend too much time here but as noted above one main difference is how the mucilage layer is kept for a day and then washed off (not fermented or scrubbed away) before drying the beans.
Removal of silver skin (aka chaff) yields toxin-free coffee
After processing of the coffee, toxins can be removed in two more ways. First is removal of the “sliver skin” and second is the actual roasting process.
If you’re not familiar with “silver skin” it is the film on the outside of the coffee bean you can see fly around as it is being roasted. Also known as chaff, most of it is removed during roasting. Physical removal of the silver skin during the roasting process could be a reason for a drop in toxins when roasting occurs. As the coffee beans expand during roasting (like popcorn) the silver skin is shed and can be removed. Think of a snake growing out of its skin.
Effects of Roasting on levels of Toxins in Coffee:
Roasting of green coffee beans actually significantly reduces the level of toxins in coffee. As of 2001, seven of the nine scientific research studies noted very large drop in toxin levels from being subjected to the a typical roasting process, between 69% and 96% to be exact.3 Another study conducted in 2008 saw a large drop in toxin levels in coffee beans after roasting as well, a 65% to 100% drop in this case!4
Fear of drinking contaminated coffee can only be dealt with effectively with educating the public of what they should be looking for in their coffee choices. Here are the things I would look for.
Wet Processing over Dry Processing
Grown at a higher elevation… over 4000ft or 1200m is pretty high (less mold grows at high elevations)
Avoid Decaffeinated coffees. Mold grows less freely in the presence of caffeine.
Avoid Blends and buy beans from a single farm. We can track the bean origin better.
Here’s how I would suggest brewing coffee to minimize toxins retained:
Cold Press:
There is no study to supporting cold press coffee eliminates toxins completely but there is also no study supporting all coffee beans produced in one farm are all toxin free. There is also no 100% proof coconut oil or coffee is good for you. All we have is our best theory.
My best theory of how to make an OTA toxin free cup of coffee is via Cold Brew (aka Cold Press).
In 2008, a study supporting a large reduction of the toxin in Moka Express (Italian Coffee) was conducted. In this method of brewing the coffee grounds stay in contact with hot water for a short time. To be exact, the reduction of the toxin in this type of brewing was 50-75% according to research. In contrast, Turkish coffee making, in which the coffee is contact with boiling water for about 10 min, has poor reduction of the toxin.4
The study tells us the less time your coffee is in contact with hot water the more toxin free it is. Following this logic, Cold Pressed/ Cold Brewed Coffee is one of the cleanest options.
Don’t know how to make Cold Pressed Coffee?
Think of French Pressing but with cold water and more time. There are a variety of ways to make it, with the time ranging from a few hours to a few days. Basically the coffee grounds are soaking in cold water before they are “pressed out.” The ratio I have heard some larger producers use is 3:5 (coffee oz. to water oz.) but I have personally found with longer soaking times 1:10 works and there is not a noticeable difference in taste. At 1:15 it starts to go downhill fast.
As you can see with efficient roasting and brewing of coffee you can drop the amount of OTA toxin you consume. When choosing coffee to buy, use our references above as your guide. When choosing a brewing methods perhaps look into cold pressing. If you really want some hot coffee perhaps cold press it first and heat it up later!
Hope this was helpful and educational… don’t be afraid of the unknown… educate yourself about your coffee and have a better coffee drinking experience.
References:
(1) Buchanan. “Caffeine Inhibition of Aflatoxin Synthesis: Probable Site of Action.” Applied and Environmental Microbiology 47.6 (1984): 1216-220. Web.
(2) “EUROPA.” Maximum Levels for Certain Contaminants. N.p., n.d. Web. 17 June 2015.
(3) Gerrit H. D. Van Der Stegen, Paulus J. M. Essens, and Joost Van Der Lijn. “Effect of Roasting Conditions on Reduction of Ochratoxin A in Coffee.” Journal of Agricultural and Food Chemistry J. Agric. Food Chem. 49.10 (2001): 4713-715. Web.
(4) Pera, L. La, G. Avellone, V. Lo Turco, G. Di Bella, P. Agozzino, and G. Dugo. “Influence of Roasting and Different Brewing Processes on the Ochratoxin A Content in Coffee Determined by High-performance Liquid Chromatography-fluorescence Detection (HPLC-FLD).” Food Additives & Contaminants: Part A 25.10 (2008): 1257-263. Web.
(5) Riley, Arthur P. Food Policy, Control, and Research. New York: Nova Biomedical, 2005. Print.
Other websites:
https://driftaway.coffee/elevation/
http://fitinafatworld.com/2013/02/07/coffee-quality-mycotoxins/
http://authoritynutrition.com/the-mycotoxins-in-coffee-myth/
http://suppversity.blogspot.com/2013/12/true-or-false-mycotoxins-in-coffee-are.html