Today’s molecule – furan

I don’t need ANY bad news about my espresso coffee!

From FECYT – Spanish Foundation for Science and Technology, via “Eurekalert

Here is their press release…

“Coffee in capsules contains more furan than the rest”

Coffee in capsules contains more furan than the rest, although the levels are still within safe health limits.

“Preparing a coffee in a drip coffee maker is not the same as making one in an espresso machine or from capsules, because these give rise to differing levels of furan”, Javier Santos, a professor at the Department of Analytical Chemistry at the University of Barcelona and lead author of the study, tells SINC.  Concern has risen over recent years about the presence of this compound in foods, because of its toxic and carcinogenic effects in animals, as well as the fact that the International Agency for Research on Cancer has listed it as a possible carcinogen in humans.

“The results, published online in the Journal Food Chemistry, reveal that higher concentrations are found in espresso (43‐146 nanograms/mililitre) than in coffee made in drip coffee makers, both in the case of normal coffee (20‐78 ng/ml) and decaffeinated coffee (14‐65 ng/ml).  The levels of these toxic products were “slightly lower” (12‐35 ng/ml) in instant coffee, but a great deal higher in those made from the capsules of a well-known brand, which showed up higher levels (117‐244 ng/ml).”

“The reason for these higher levels is due to the fact that hermetically-sealed capsules prevent furan, which is highly volatile, from being released, while the coffee makers used to brew this coffee use hot water at higher pressures, which leads to the compound being extracted into the drink”, says Javier Santos. The longer that coffee is exposed to the air in cups or jugs, meanwhile, the more the furan evaporates. ”

“Different values, but not dangerous: The researcher stresses that, in all these cases, the levels of the substances found are within the limits considered to be “safe” to health. In fact, the team has estimated the amount of furan ingested as a result of coffee consumption in Barcelona, obtaining values of 0.03‐0.38 micrograms/kilogram of body weight, which is less than the maximum acceptable level (2 μg/Kg of body weight). In order for furan ingestion to exceed the maximum acceptable values, a person would have to drink at least 20 cups of capsule coffee or 30 espressos per day (for the brands with the highest furan content), or 200 instant coffees. These estimates were made on the basis of 40 ml cups and an average body weight for coffee drinkers of around 70 Kg.”

“The study also shows that furan concentrations are lower if coffee is roasted at low temperatures over a longer time (140ºC for 20 minutes) than in coffee roasted under usual conditions (200‐220ºC for 10-15 mins).”

Furan, like acrylamide, is one of a group of carcinogenic substances that can form when foods and drinks are subject to heat treatment. They are the result of a reaction, known as the Maillard reaction, between carbohydrates, unsaturated fatty acids and ascorbic acids or its derivatives.”


M.S. Altaki, F.J. Santos and M.T. Galceran. “Occurrence of furan in coffee from Spanish market: contribution of brewing and roasting”. Food Chemistry 126 (4) 1527, June 2011 (Available online December 2010). Doi: 10.1016/j.foodchem.2010.11.134.

Pretzel logic

Final lab session of our Food Chemistry class this year.

20100311 AR pretzel ANNOT

An experience of the effects of pH on browning reactions.

We make a variant of traditional soft pretzels, using a rather leaner formula than often used [for us no milk or eggs]. The loss of lactose from the milk and glucose from the egg might have contributed to our failure to get the same level of color development we saw last year when we used a full rich formula with egg and milk.

20090312 pretzels

Still it is a great way to experience the effect of pH shift on the color and aroma generated by primarily Maillard browning, allthough at pH 14 in the 4% NaOH, other reactions are very likely.

2010 formulation


2009 formulation

untitled 2009

A poolish is a 50:50 mixture of flour and water BY WEIGHT with about 0.1% of the flour weight as dried [instant] yeast [NO SALT] that is allowed to ferment around 16 hours before being added to the final dough.

Interesting post from Khymos – and some other things


Martin Lersch has a post (Dangerous names)  inspired by an article entitled  “If It’s Difficult to Pronounce, It Must Be Risky” by Hyunjin Song and Norbert Schwarz of the University of Michigan and published in Psychological Science


So… you think there’s nothin’ obviously dangerous sounding in the ciabatta pictured below ? – think again –

It has 80 baker’s % DHMO

and it has a fair splash of durum flour, which is enriched in 1,3,3-trimethyl-2-[(1E,3E,5E,7E,9E,11E, 13E,15E,17E)-3,7,12,16-tetramethyl-18-(2, 6,6-trimethyl-1-cyclohexenyl)-octadeca-1,3,5,7,9,11,13,15,17-nonaenyl]cyclohexene

This chemical gives the bread a nice yellow color and seems to carry more flavor as do some other non-polar triacylglycerol-soluble molecules.


(recipe adapted from “Bread Baking: An Artisan’s Perspective” by Daniel T. DiMuzio)

BUT – if you like your chemicals silly and have a open-minded sense of humor then this is the site for you: authored by Paul May of the Bristol University School of Chemistry