Barrels made from Kiri wood

Eder experiments!

When one speaks of wooden barrels, one usually means barrels made of oak. In this country more precisely from German or European oak. However, these trees have the characteristic of growing very slowly. This requires the work of several generations of foresters. Because such a German oak is harvested on average only at the age of 200 years. In the course of decades, many things happen to an oak tree that make the work of the cooper more difficult later on: there are storms that affect the growth, wars in which ammunition fragments get into trees, trees get twisted – without it being visible from the outside – or are simply seen as a tidbit by deer and co. in recent years.

Withou wood – without us!

We don’t want to do without “our” wood at all, but sometimes it’s time to go new ways, to be brave and to experiment.
So we looked at which tree grows quickly, can be grown sustainably and is suitable for barrel construction.
In the course of our research, we then found the tree that is very often the opposite of the slow-growing oak in its characteristics: Kiri!

We were not particularly creative in finding a name for this tree, which has only recently become native to Europe. Kiri is Japanese and means “wood”. Other names for the kiri tree are bluebell tree, emperor tree or emperor paulownia.

So what gives Eder the idea of working this wood into barrels?

First of all, the kiri tree is very fast growing. It grows up to 5 meters a year and can be harvested after only 15 years. It forms a straight trunk, which is essential for the barrel staves later on, and makes few demands on the soil and climate. Only in the first years the roots and trunks need to be protected, after which the tree defies frost and lack of nutrients.

The light-colored wood, originally native to central and western China, is stable yet pliable, which qualifies it for barrel making.

Prototype

We have now built the first prototype in our cooperage and have also already started tests with neutral alcohol to see how Kiri wood affects the taste.
My guess: Due to the rapid growth, the wood should be quite large-pored, and wood sugars are deposited in the pores of the wood, which are released by the toasting. So I expect the wood to give off slightly sweet notes with influences of spice.

The smell of the wood can not be called much other than neutral but we know from other woods, such as oak, chestnut and especially walnut how much the toasting can affect the taste. Our coopers report that when toasting the Kiri wood, it smelled like delicious cotton candy.

To look at the whole thing more from the scientific side: According to analytical and sensory evaluations, Paulowina imperialis is a highly aromatic wood with high cellulose and lignin content, which can already be surmised from the physique of the oversized leaves. Due to the high content of lignin and hemicellulose, heat-reduced toasting, which can also be applied by means of electric heat and secondary heat sources (e.g. hot stones), can prevent smoke aromas such as gujacol during toasting, but high sugar molecules can be realized on the surface of the wooden barrel by splitting the ingredients.

As a result, wooden barrels are created that, unlike barrels made from traditional wood species and known toasting, offer high aromas in the form of sweetness and vanilla when aged with distillates wines or beers.

Due to the open pores and rapid growth, it is probably to be expected that barrels made of Kiri wood are more prone to leakage than fine-pored variants. It is therefore essential that if you embark on this experiment, you always pay attention to the barrel, check it thoroughly on a regular basis, and also expect that staves may need to be replaced with those made from other woods.

We are still at the very beginning of this series of tests, and we are all very curious to see where the journey will take us and how the barrel and alcohol will develop over time.

As you can see, even a company that carries out a very old craft such as cooperage is ready for innovation and experimentation. We are curious to see where this journey will take us and what exciting projects we will encounter next.