Google Ngrams

[uncle tom]

Have just come across this:

https://books.google.com/ngrams

Try entering various port terms - the results are rather interesting.

Tawny port was far more often referred to in the 19C than Ruby port, the term Vintage port makes no appearance prior to the 1860s and only really took off in the 1920s, Late bottled vintage had brief mentions from the 40s but took off in the mid 80s..

And the term Port lodges does not appear in the literature Google have surveyed for this before the late 1960s..

[Andy Velebil]

Here is something I wasn't aware of. I thought this happened far earlier than 1926.

In 1926, the government created the Bonded Area, or Entreposto, in Vila Nova de Gaia, an area that was to act as an extension of the demarcated region. All companies connected to the Port Wine trade were forced to build lodges within this area if they wished to age their wines. In practice, this was the end of all trade direct from the Douro.

A somewhat informative read...

http://www.ivdp.pt/pagina.asp?idioma=1&codPag=9&