Is Apple Juice Flammable? (A Comprehensive Overview)

Is Apple Juice Flammable?

No, apple juice is not flammable. Apple juice is made of water and the organic material from the apples. This organic material, if isolated from the water, would be capable of catching on fire.

An apple juice sample that was left open for weeks will have had some of its water evaporated and some of its organic content converted into alcohol via fermentation. In such an event the apple juice could become a flammable material given the low amount of water.

Do Apples/Apple Juice have Alcohol?

Yes, apples contain alcohol (ethanol). The percentage of ethanol in apples is relatively low (less than 0.5% in weight). Since most apples are made up of water, the ethanol and other naturally occurring flammable substances are not enough to cause a regular apple to catch on fire.

Many other fruits contain ethanol, examples are oranges, grapes, ripe bananas. But for all of them the amount of ethanol is about the same as for the apples. Fermented or rotten fruit or vegetables, on the other hand, contain much higher levels of ethanol.

Apples and other fruits can also be processed and distillation to obtain ethanol. This ethanol is flammable, even if it is mixed with up to 60% water.

If an apple is exposed to flames or heated for sufficient time it will likely catch on fire at some point. Once most of the water has evaporated, the remaining material will be composed majorly of organic substances that can catch on fire with ease.

If apple juice is fermented, the sugars present in it will be transformed into ethanol by the fermentation bacteria. In this case the amount of ethanol that can be obtained from the apples or apple juice is much higher than by only distillation.

That means that an apple juice that underwent fermentation for a sufficiently long time can pose a fire hazard.

How Long Does it Take to Ferment Apple?

That depends on a number of factors, overall it can take as little as a few weeks or as long as two months. This transformation occurs by the process of fermentation. Which is caused by enzymes from microorganisms.

In biochemistry fermentation is the process by which sugars are used as an energy source by enzymes in absence of molecular oxygen (O2). Different substances are obtained from different sugars. In the case of apples, glucose is transformed into alcohol (ethanol).

Are Dehydrated Apples Flammable?

Dehydrated apples do normally catch on fire. The same goes for any fruit, leaf, vegetable that has had its water content completely removed. The remaining material of a dehydrated fruit consists of many different organic substances.

In the case of dehydrated apples catching fire, the fumes released will be mostly carbon dioxide and water, but other gases will also be present in smaller quantities.

Are Carbohydrates in Pure Form flammable?

Carbohydrates in apples amount to approximately 14% (in weight). The main carbohydrates found in apples are fructose, glucose and sucrose. And they can only catch on fire under very specific conditions, examples are:

  • If the sugar is exposed to highly oxidizing agents.
  • If the sugar is in very finely divided particles suspended in the air and a large amount of heat is applied.
  • If the autoignition temperature is reached, as is the same for any material, by definition.

Does Apple Juice Conduct Electricity?

Yes, apple juice does conduct electricity. If the juice is diluted it should conduct electricity better than pure water, given the presence of chemicals (from the apple) that can act as electrolytes.

Since apple juice does conduct electricity, it hardly accumulates static electric energy. Dehydrate apples, on the other side, can accumulate static electrical charge.

Can Water Burn?

One answer to that question is that it is not energy favorable for water to burn. When methane burns, for instance, the methane molecules and the oxygen molecules from the air are transformed into water and carbon dioxide.

The above mentioned transformation is an example of a combustion reaction. In most cases when something burns, the material being burned is going through an oxidation reaction.

The heat that is produced during a combustion reaction comes from the formation of the chemical bonds in the water and carbon dioxide molecules.

So for water to go through a combustion reaction the overall process would need to be energetically favorable. In general, for that to happen a very reactive material (substance with weak chemical bonds) would need to be involved.

For instance, alkali metals (e.g. sodium, Na0) will react strongly with water to form hydrogen gas (H2), which is highly flammable along with sodium hydroxide (NaOH). This reaction is very dangerous because it produces a lot of heat, which can cause hydrogen gas to ignite.

The reactivity of apple juice and other fruit juice is close to the reactivity of water towards alkali metals.

Does Apple Juice Contains Cyanide?

If the juice was made from seeds containing apples, the juice will contain a very small amount of amygdalin (C14H15NO7). Amygdalin can be converted into cyanide ions (CN) by beta-glucosidase.

That being said, the amount of amygdalin in apple seeds is around 3 g/Kg (3 grams is roughly the weight of 4 to 6 seeds) and each gram of amygdalin can yield at most 0.08 grams of cyanide ion.

Some Healthy Nutrients present in Apple Juice and Apples?

The chemical (or phytochemical) composition of apples varies between the different species of apple trees and there can be some differences in their compositions during the time of maturation of the fruit.

The processing of apples for the production of apple juice can greatly affect the composition as well.

A non processed apple will normally contain the antioxidants substances: catechin, chlorogenic acid, phloridzin and quercetin. 

Besides the water, which makes up around 80% of apple juice also contains sugars, oligosaccharides, polysaccharides, malic, quinic, tannins, malic acids, vitamin C, minerals and many others.

Pasteurized and Unpasteurized Apple Juice

Pasteurization is a process performed by the food industry to eliminate microorganisms by applying heat.

In the case of apple juice the recommended heat is lower than most food supplies because a is its high acidity. Apples naturally have a certain level of defense against microorganisms.

The U.S. The Food and Drug Administration recommends heating ramping from 71 ºC to 82 ºC, with specific minimum intervals each 3 ºC. This heat curve is enough to eliminate Cryptosporidium parvum with 5-log reduction.

Pasteurization is fundamental for health safety, there have been tens of thousands of cases associated with unpasteurized juices and ciders over the past 20 years all over the world.

Pathogens commonly related to these food-borne illnesses are bacteria, parasites and even viruses. Among bacteria, the major ones include Escherichi coli (E.coli), Salmonella bongori, Salmonella enterica, Cryptosporidium, Clostridium botulinum.

There have also been many reports of Hepatitis A virus.


Some facts regarding apple juice potential fire hazards have been discussed. Apple juice does not catch on fire unless very specific processes are undertaken.

Flammable substances can be obtained from apple or apple juice, though the required procedures for that are not common in everyday life.

Some aspects in regards to the nutrition value as well as the potential hazards associated with apples and apple juice have been exposed.

Frequently Asked Questions (FAQ): Is Apple Juice Flammable?

Why does apple juice taste like metal?

According to a study published in 2007, at least one of the contributors for the metal taste is 1-octen-3-one (C8H12O) and unsaturated ketone. Besides this ketone, other compounds were also suggested to be responsible for the off-flavor of apple juice: 2-methyl-1-penten-3-one, (E)-2-heptenal, 6-methyl-5-hepten-2-one, and (E)-2-octenal.

In this study photooxidation was radiated in the apple juice for controlled amounts of time.

These organic substances were identified by a range of spectroscopic analyses.

Is apple juice pasteurized?

Industrialized apple juice must go through a process of pathogens elimination. The most common process with that purpose is pasteurization.

Can unpasteurized juice make you sick?

Yes, there is the possibility that unpasteurized juices contain harmful bacteria or viruses or parasites. In the case of doubt if the juice was or wasn’t pasteurized that information must be provided along with the product.

Why does apple juice explode?

In some rare cases the yeast from the juice can go through fermentation even in sealed cans. This process can increase the pressure within the can. This happens because fermentation causes the biological synthesis of volatile compounds. Building up of these volatile compounds can increase the pressure to the point of fracturing the cane causing the high pressurized mixture to quickly (maybe violently) explode.

How Should Apple Juice Be Stored?

Sealed recipients of canned apple juice don’t need to be kept in refrigeration. But they need to be kept protected from light (to avoid oxidation of the fruit content by light). It is also important to keep air ventilation to avoid proliferation of microorganisms.

Recently made apple juice or open canned apple juice needs to be kept in refrigeration and resealed tightly. Once opened, canned apple juice should be consumed in a short amount of time.

The refrigeration temperature should be at or near 0 ºC to prevent proliferation of microorganisms.

Why does eating apples increase appetite?

That has to do with the fact that apples contain a lot of sugar but not a lot of fiber. This causes a high sugar spike absorption followed by a sudden decrease in sugar levels, that can make one hungry.


Midori Hashizume, Michael H. Gordon, and Donald S. Mottram

Journal of Agricultural and Food Chemistry 2007 55 (22), 9177-9182

DOI: 10.1021/jf0715727

Determination of ethanol in apple:

Gorgus E, Hittinger M, Schrenk D. Estimates of Ethanol Exposure in Children from Food not Labeled as Alcohol-Containing. J Anal Toxicol. 2016;40(7):537-542. doi:10.1093/jat/bkw046

Information on chemical composition of apples:

Dianne A. Hyson, A Comprehensive Review of Apples and Apple Components and Their Relationship to Human Health, Advances in Nutrition, Volume 2, Issue 5, September 2011, Pages 408–420. DOI:

B. Jarvis, CIDER (CYDER; HARD CIDER) | Chemistry and Microbiology of Cidermaking,

Editor(s): Benjamin Caballero, Encyclopedia of Food Sciences and Nutrition (Second Edition), Academic Press, 2003, Pages 1318-1323. DOI:

Information on an incident with exploding apple juice cans: (Accessed on march 28th 2022)

Information on unpasteurized juice: (Accessed on march 28th 2022)

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