The most popular of my many Linkedin
posts has been one of some staves in various stages of toast and char....
Going a bit deeper today on this.
Toasting at Kelvin Cooperage is always done over oakwood fires for anywhere between 10-15 minutes (depending on customer spec). This provides excellent heat penetration and breakdown of lignin - producing extractive compounds.
We then allow the internal surface of the barrel to combust (using a plate) and the barrel is allowed to char for time.
#1Char is about 25-35 seconds
#2Char 35-45 seconds
#3Char 50-60 seconds
#4Char 60-75 seconds
Everything we do is based roughly on time with a heavy reliance on the human element to ensure each barrel comes out consistently toasted and charred using visual cues.
Those producers that strictly use timers can end up with vast variance in outcomes given the extreme number of variables involved in heating white oak.
You have to take into consideration, grain density, moisture content, ambient temperature, barrel temperature out of the steam tunnel and onto the fires.
All of these play a critical role in how the wood will react to heat exposure and thus the times we toast and char to get uniformity in the end product.
Our barrels look, smell and feel different - plus they are very photogenic!