According to the wwmt, 

The Dragon’s Milk Solera was described as a 10% alcohol by volume, foeder-aged ale — a foeder is a massive oak barrel — that would fall under the category of a strong ale. Each batch of the unique ale will be blended with an original batch after they are allowed to age.

“We plan to label each batch with the pull number so drinkers can join us on the journey,” New Holland Brand Manager Dominic Berquiest said. “The aging and blending brings our brewers and cellarman a new set of challenges, but they have more than risen to the occasion and we’re excited by the results.”

Read more at source: wwmt