"You aren't a vegetarian, are you?" Mario Sacilotto asks me. He seems kind of worried.
The German entrepeneur with Italian roots is definitely not an eco-freak.
He enjoys a good grill steak, barbecued in his garden in Alfter, a small town near Bonn, Germany.
Although he's not a native to the eco-scene, his new startup Grillmais (which means "BBQ corn" in English) has brought him straight to it.
Sacilotto sells an alternative charcoal product for barbecuing: corncobs, the central core of an ear of maize — what you get when you've nibbled off all the kernels.
It's more environmentally friendly than charcoal, he says, adding that it also has a lot of practical advantages for the 'cue connoisseur.
Sacilotto tears open a paper bag and dumps dozens of light-yellow and reddish corncobs into his barbecue grill. Then he pours lighter fluid over them, and sets it alight.
Flames soon flicker among the corncobs.
"Now we have to wait 10 to 14 minutes before we can put the meat on," Sacilotto says.
He adds that this makes his product superior to charcoal, which has to burn for at least an hour before you can considering putting food on the grill.
"I have known this way of barbecuing since my childhood. My uncle in Italy always had a cornfield, and if we had a barbecue down there, we always used corncobs for the fire."
When he returned to Italy recently for a holiday with some friends, he remembered this tradition and wondered: Why not bring the corncobs to Germany and sell them as a charcoal alternative there?
Sacilotto purchases the corncobs in Italy, where they are leftovers from the production of canned corn and cornmeal.
He has them transported to Germany, and sells his product at local supermarkets and hardware stores, as well as over the internet.
Sacilotto promotes his product as a solution to fight loss of rainforests due to charcoal production.
Dirty deals with tropical wood
Germans are among the folk who love to barbecue, and like in many places around the world, their favorite way to do it is on wood charcoal. This lends a tasty smoky flavor unrivaled by other forms of charcoal.
But such charcoal is made from wood — by heating it in the absence of oxygen.
According to wood expert Johannes Zahnen of WWF, 250,000 tons of charcoal are used in Germany each year, mainly for summer barbecues.
"That represents 2 to 10 percent of all wood consumed in Germany," he tells DW.
A recent analysis of 36 charcoal products from German supermarkets, commissioned by WWF and the German public television channel NDR, revealed that charcoal quite often contains tropical wood.
This was even true for products labeled with the Forest Stewardship Council (FSC) certification, and for products stating on their package that they only contain German wood species.
Read more: The difficult task of tracking deadly wood
"The problem should not be oversimplified," cautions Gerald Koch, a scientist with the Thünen Institute, a German research body that conducted the charcoal analysis. "Not everything that comes from the tropics is illegal."
Koch points out that there are sustainably managed plantations in the tropics as well. Moreover, some acacia species are spreading as invaders throughout Namibia. If their wood is cut and made into charcoal, it's a good thing, he says.
But the problem is, you can never be completely sure where the wood is coming from.
Through examining the charcoal with a microscope, scientists at Thünen Institute can distinguish from what kind of tree species the wood was originally made of, including whether it is a tropical species or not.
"However, no [analysis] method in the world can show whether the wood came from a nature reserve, or from a sustainably managed plantation 50 kilometers away," Koch explains.
Customers depend on information provided by the producer to know how sustainable the charcoal is — and unfortunately, this information isn't always reliable.
"If a charcoal is labeled as 'only from German wood' and we find tropical tree species in there, then this is very suspicious indeed," Gerald Koch says.
Norbert Jedrau, director of the Barbecue Industry Association Grillverband (BIAG), an industry-oriented organization, points out that charcoal does not necessarily always come from trees cut down for that purpose.
"It's also produced from wood waste from the furniture industry, for example."
Gaps in regulation and certification
How is business with charcoal from tropical forests possible in Europe, anyway?
The European Union Timber Regulation does prohibit illegally logged wood from entering the EU. But that regulation doesn't include charcoal.
"It simply wasn't considered when the regulation was passed," wood scientist Gerhard Koch says.
And where there's a green market niche, there's a way ... three guys from the south of Germany established Germany's first charcoal with organic certification, making sure it comes only from sustainably managed forests.
"On a trip through Ghana we got to the bottom of the charcoal business in Europe," entrepeneur Aaron Armah tells DW.
When traveling through the African country, charcoal kilns were omnipresent. They talked to people bringing wood from native forests to those ovens.
"Even FSC is not a reliable label anymore, as control mechanisms aren't effective anymore due to corruption," Armah believes.
The three entrepeneurs sell charcoal from German forests; the wood is coked in a plant in France, where they produce electricity from the heat generated in the process, Armah says.
"With our charcoal, everyone can barbecue without feeling guilty."
WWF's Johannes Zahnen supports the startup's approach.
"There is practically no overexploitation of forests in Germany," he says. As long as they truly don't import wood from other countries, "then this is a good option."
But Zahnen points out that the quantity of charcoal produced this way wouldn't be enough for the market if everybody switched to this sustainable product.
Barbecuing on all kinds of waste
By now, several ideas and products are available in Europe as an alternative to wood charcoal.
The company Oliobric, for example, sells briquets made from olive pits.
Leftovers from pressing olives are dried, burned in the absence of oxygen and pressed into BBQ briquettes "that burn extremly hot and for a long period of time" Oliobric's director Gerhard Erning tells DW.
As in in Mario Sacilotto's case, it's not a completely new idea.
"My business associate is married to a Greek, and in Greece they have been using this biomass as a fuel for their ovens for ages."
Erning sells his product in organic supermarkets in Germany and in grocery stores in Switzerland.
There are also charcoal alternatives made from coconut waste or from grapevine wood, which has to be cleared away on a regular basis anyway.
Which is the most sustainable of them all?
Zahnen is cautious in recommending any of the charcoal alternatives made from materials other than wood.
"You really have to look thoroughly into the production process," he says. "Be careful not to replace one evil by another. There might be a drawback."
Coconut plantations, for example, could easily replace native forests.
Apart from that, Zahnen thinks that too little charcoal is able to be generated from those alternatives to be of wide use.
"We still think that the FSC certification is the right tool for the mass market," Zahnen says. "But they do have to get better and have tighter controls in certain countries."
Jedrau agrees, saying that the industry is in contact with FSC, and that the standards are in further development.
Greenpeace announced in March that it will not renew its membership with FSC because "it's an imperfect tool for protecting people's rights and improving forest management."
If you really want to BBQ eco-consciously, use gas or electricity, Zahnen says: "Those grills only generate heat when you really need it."