Alcoholic strength of Port

[JacobH]

I have to confess that I don’t really understand the subtleties of winemaking. I’m not sure I’d know a hydrometer if I met one walking down the street, and I always get fining, filtering, sulphuring and cold stabilisation confused.

Therefore, please forgive me if this is not something of any consequence, but I’ve always been intrigued by the varying strength of Port. I believe that, based on Mayson’s book, Port should be between 19% and 22% (excluding a type of white Port which I’ve never seen or heard of elsewhere). Whilst that’s not a huge difference; it still represents a variation of around 15% in strength.

I also note that individual houses seem vary the strengths of their individual vintages. For example, to grab some easily accessible pictures on the forum, Taylor ’77 is 21%; ’63 is 22% and ’45 is 19%. I’m not sure such variation is replicated elsewhere with other styles of wine, but I may be wrong.

I therefore wonder whether the difference in strengths is enough for the drinker to notice? I often wonder if spirity stronger Ports suffer from the extra aguardente that is presumably added during the process, but perhaps I am just imaging that. Alternatively, is strength simply used as a tool by the winemakers to produce a ‟house-style” of the Port?

I’d be interested in hearing any thoughts!

-Jacob

[DRT]

Dilema:

1. Jacob has posted a very interesting question
2. I have 45 books about Port sitting on a shelf beside me, many of which will contain useful info on this subject
3. It's 12 minutes past midnight and I have to be on a train to London in 7 hours

Hmmm?

If an answer appears here in 2 hours I have made the wrong choice

[g-man]

Dilema:

1. Jacob has posted a very interesting question
2. I have 45 books about Port sitting on a shelf beside me, many of which will contain useful info on this subject
3. It's 12 minutes past midnight and I have to be on a train to London in 7 hours

Hmmm?

If an answer appears here in 2 hours I have made the wrong choice

and #2 can flow into #3 on the train to london

[Andy Velebil]

Derek,
Shame on you, you should have been in bed a 1/2 hour ago

[uncle tom]

I would also have to trawl my books to be sure, but from memory I recall learning that for many years the amount of aguardente to be added was an officially dictated proportion, without reference to the alcoholic strength that the wine had achieved through fermentation.

It follows that you would expect some variation of strength in the final products.

Tom

[Glenn E.]

My memory is the same as Tom's, and in fact I believe the ratio is 4 parts Port to 1 part aguardente. The aguardente is (I believe) required to be 77% alcohol, so the final content of the Port is entirely dependent on how long the grapes are allowed to ferment.

Port in the US is almost always 20% these days, though I have on occasion seen slight deviation. The 1995 Quinta do Crasto magnums I just purchased, in fact, are 19.5% and I recall a bottle a while ago that was 23%. Yes, 23% - technically outside the limits imposed by the IVdP, yet it had a Selo and everything. I wish I'd saved the bottle, but at the time I didn't realize it was anything strange.

[uncle tom]

In the UK, anything over 22% is taxed as spirits rather than fortified wine, at a rate that would roughly double the duty paid.

Tom