You know you might be on to something here ...

The most aromatic Makrut have really bumpy fruit and thick spines/thorns; prevalent with fruit/seeds brought in from Thailand. The fruit is nearly all seeds and oil; with very little juice.

There is another variety with smoother fruit and smaller thorns that are not as aromatic (but still nice); and tend to bear juicier fruit with less oil. This seems more prevalent in the West.

I wonder if the latter are somehow crossed with other highly similar smooth skin papedas, specifically either Khasi from India or Westeri from the Philippines.

Since the aromatic compounds are in the oil; maybe the juiceless, thorny variety might actually be better!

In any case, you might be able to remedy this somewhat by only using the very freshest leaves (should be full size for your tree but still have a waxy sheen) as those are the most aromatic. The dull older leaves are the ones with only the vague citrus/lime aroma (since the highly volatile scent would have been long gone).

This post was edited by farm96744 on Mon, Mar 3, 14 at 17:19

@farm96744
I didn't realize that the fruit was different too. I just thought it was only the thorns on the tree. Thank you for the great explanation! Now it make a little more sense to me.

I stopped by Lowe's today.They had the "Western" large leaves, small thorns, round smoother fruit version labelled as "Kaffir Lime".

I pinched off a leaf and lo and behold it truly did not smell like a true Makrut (compared to the ones I had gotten started from seeds from a Laotien friend). It was a subtle difference but nonetheless a significant one, the smell from the Lowe's tree was more musky and less sweet, unlike my seedlings which have the familiar Thai restaurant smell.

This really suggests to me that our commercial Makrut in the West have somehow been outcrossed. If I had to guess, this probably happened in the Philippines due to the close ties with the US. There (in the Philippines), the Westeri is used interchangeably, and that could have been what is was crossed with.

This post was edited by farm96744 on Wed, Mar 5, 14 at 22:16

Very interesting. I was wondering if it was a West vs East tree.

Can you please send me a PM, click on my page. I have a question to ask but don't want to post. I can't PM you because you disable that feature.

Thanks for helping me to try and solve this mystery.

I got one from Lowes' too and the thorn is shorter with smooth skin fruits. But the leaves are definitely magrood. Some people suggested that it could be the stock plant (from grafting) taking over but then the aroma should be different unless there is another plant with similar aroma.

Very interesting! I have one from Four Winds Nursery, and it has small thorns, but I would not call the fruit smooth. It's quite bumpy and quilted looking, but it's almost seedless and very juicy.
Very acidic with a slight bitter aftertaste, the zest is very aromatic. I've used the leaves to cook with and they were nice and fragrant, but I have nothing to compare them to.

Is the name Markrut really a variety name or more of a category name, such as "navel" or "mandarin"? That would explain a lot.

Makrut does not refer to a special variety in Thailand. It is just the Thai word for kaffir lime.

In the U.S. the ones from the big box nurseries tend to come from growers who graft their plants and thus their scion comes from a selection that has shorter thorns. None of these are named varieties. The one I have from Lowes has short thorns and a subtle cologne-like element to the leaf scent.

My mother planted some seeds of this kaffir lime from Lowes and the seedlings all have those 1inch or so thorns, like the ones from the Asian nurseries here. The ones sold there are all seed grown and I believe this is the one you want for culinary use.

Bushes of 12 years old kaffir limes tree with 1 mm small thorns. Very helpful for many dishes, marinate fish and chicken. More oil than juice. Mature fruits have full whole juice.