PORT TRIVIA

[Roy Hersh]

Evaporation plays a major factor in the costs and even logistics of aging Tawny Port in wood. Using a 20 year old Tawny Port as our example, if vinified in 2007 and theoretically ready for sale in 2027 (20 years later), how much Port would you need (considering the evaporation that would take place over that period of time) to produce one liter of the 20 year old Tawny?

[Glenn E.]

The number that immediately popped into my head is 30% but that may be the "angel's share" for Irish Whiskey. At any rate, that would mean you'd need roughly 1.5 liters in 2007 in order to bottle 1 liter in 2027?

[Roy Hersh]

No stogie to hand out yet.

[Jan-Tore Egge]

Isn't the evaporation rate for cognac approximately 3 percent per annum? If so, and if it's the same for port, what you're left with after twenty years would be (0.97 to the power of twenty) times the amount you started with. That's 0.5438, which means you need 1.8389 litres. But the evaporation rate could be wrong, and any racking is not taken into account.

[Roy Hersh]

Jan-Tore,

You are pretty close to getting the gist here. Your method of calculating is spot on.

[Frederick Blais]

Roy, you did not say if the tawny was aged in the Douro(~3%) or Gaia(~2%) So I guess Jan gets 50% of the answer :)

[Andy Velebil]

Roy, you did not say if the tawny was aged in the Douro(~3%) or Gaia(~2%) So I guess Jan gets 50% of the answer :)

or if its in new humidity controlled cellars :devil:

[Roy Hersh]

Frederick's numbers are not accurate. As you will read in this month's in A Question for the Port Trade (at least subscriber's will ... this is the best and most educational one ever) thanks to Derek's great question, there is no specific percentage that can be attributed to Gaia or the Douro for evaporation.

My question is based on how much evap takes place in over a 20 year period with a Tawny Port and is for one liter, based on an actual situation. The way to calculate is important, knowing the average percentage is important, but understanding the expense and outcome are the real dynamics that had me list this here.

Some cask storage in the Douro has less evaporation than some Gaia Lodges. Some Gaia Lodges have 4% evaporation and quite a few have 3% too. The rate of evaporation can change within the same cellar based on the thickiness of the walls, which direction they face (exposition to the sun), where in the cellar ... closer to the wall or the middle of the room, and even if it is on the bottom tier or at the very top of a stack of pipes. So making up arbitrary numbers is not going to get it done.

The good news is that if nobody gets the answer before Monday when the newsletter should reach your hands (latest is Tuesday) then you'll be able to read it there.

[Derek T.]

Frederick's numbers are not accurate. As you will read in this month's in A Question for the Port Trade (at least subscriber's will ... this is the best and most educational one ever) thanks to Derek's great question, there is no specific percentage that can be attributed to Gaia or the Douro for evaporation.

I am looking forward to reading the responses. One of those who responded emailed me to tell me he had done so but didn't tell me the answer!!!

Derek

[Roy Hersh]

Derek,

I've included the 5 best and most detailed responses. None is actually the same and opinions vary between these renowned gentleman, some of whom reveal rarely seen inside info, to my astonishment.