Could CRISPR improve decaf coffee taste?

As well as allowing the nutritional value of foods to be enriched, gene-editing could also be used to enhance the taste of certain items, and one of my favourites has been highlighted as a potential target: coffee. The delicious taste of the bitter beans are one of the main attractions. But not everyone is keen on caffeine, although many are not fond of decaf either; and while modern varieties are better than their predecessors, many still claim it just doesn’t have the same edge. So could gene-editing hold the key to crafting the perfect non-caffeinated joe? Here to help us answer that is geneticist Thomas Merritt from Laurentian University, who spoke to Chris Smith...

Chris - Thomas, you must be one of the first guests actually to do the experiment before the interview even started! He's tweeted a picture of himself holding a cup of coffee. And in fact, one of our other Twitter followers, Thomas has said, "was that a much bigger mug before you did CRISPR-Cas9 on it, because it looks far too small to me!"

Thomas - It is not. And I will say full disclaimer, that's also not decaf. I tried to convert myself and I didn't make it.

Chris - I'm in good company then. When we make decaf, Thomas, how is that actually done?

托马斯,所以有几个不同的答案s to that. It all comes down to extraction. We try to take out the caffeine and leave everything else in. Historically, this was done with benzene, which is just terrible. There's some better processes. Now we can use something called the Swiss water method, or we can actually use super critical CO2. It really comes down to, can you pull out the caffeine and leave everything else there? With Swiss water, we actually try to put everything else back and then take the caffeine out. In all cases, you never get quite the same coffee at the end of the process.

Chris - So how might gene editing solve this for us then?

Thomas - It ends up that there's some really interesting coffees out there. Most of the coffee that we're drinking is Arabica, and there are varieties of Arabica out there that don't make caffeine. There are sort of natural mutations that have happened and have knocked out the pathway. And so we're looking at those thinking, well, could we do the same thing and knock out the genes? There are a series of enzymes that are part of the caffeine process and we could simply turn those off.

Chris - And if you do that, does that not in and of itself effect the flavour because caffeine is a bitter tasting chemical?

Thomas - I think that's an unknown. It seems like maybe but we can certainly get closer to a coffee that tastes like coffee, the coffee that you expect by creating a coffee that just doesn't have it in the first place. So a caffeine-free coffee, whether it's going be exactly the same, I don't think anybody knows the answer to that yet.

Chris - What could be the consequences for the coffee itself? It presumably makes caffeine for a reason. Some have speculated that plants put caffeine into their nectar to addict bees to their flowers so bees are more likely to pollinate them. I mean, there is some evidence to support that, but it's also a natural insecticide. So if we started robbing this stuff out of the plant, does it have knock on consequences?

Thomas - That's a really interesting point. And again, we're not going to know the answer until we try it. Traditionally, we think of caffeine as being an insecticide. It's a way that has evolved in a number of different plants, not just coffee, to limit the way that insects chew on the plant. So what happens when we take that away? We're not entirely sure. I think we're looking at an agricultural situation and not a wild plant, and there are other ways that we could be able to manage those pests.

Chris - In the past when we've wanted a crop with a certain characteristic. What we've done is to go and find crops that have another characteristic, cross them together and hopefully get the best of both worlds. Could we not do that with coffee to find a low caffeine variety, cross it into an Arabica that tastes great and get a low caffeine, good tasting Arabica?

托马斯- p的阿拉比卡咖啡articular really doesn't like to cross. It's one of the reasons that varieties of coffees taste like varieties. It's easier with Robusto, which is the other really dominant coffee that's grown in the world. But it's a long process and coffee takes about 25 years or so, to get an adult plant that's producing enough beans to be a commercial plant. With genetic editing, we could do this in something like five to seven years, and we could actually be testing much sooner than that. So in the space of a couple of years, you could test whether the editing was efficient and you'd actually created a plant that was potentially caffeine free.

Chris - So slightly longer than it takes to make a cup of coffee, but not much. Thomas Merritt. Thank you very much, indeed, for explaining it for us.