The IDVP’s Seal of Guarantee

Selo de GarantiaAbout a year ago, there was a very interesting discussion on the FTLOP Forum re: the IVDP’s Selo de Garantia (or “Seal of Guarantee”). Many questions were raised about what its real purpose is and other aspects about the Selo. To obtain the truth, the whole truth and nothing but the truth … it took me a long time to find the answers to some important questions.

I will not bore you with the details of my journey through the long and winding road that finally led me to the TRUTH. Suffice it to say, it was as circuitous as the meandering turns in the Douro River itself and after an absolutely relentless search, I was finally provided the portal. Upon having my email returned with a slew of information, I celebrated with a wonderful bottle of Port. Here are my findings and answers to questions raised way back when.

1. Exactly what year, did the Selo de Garantia first appear on Port bottles?

The Port Wine Institute, (IVP, which in 2003 became the IVDP to include Douro Wines) took form in 1933. In historical perspective, (for American readers) this was the same year that Prohibition ended! Just eight years later, beginning in September 1941, the Selo de Garantia became mandatory on all Port wine bottle necks. The very first seal, though not mandatory, appeared in 1934.

2. I am often contacted by complete Port loving strangers to help authenticate Port bottles for them. The Selo de Garantia would be a very useful tool. Can I get some help with it?

For example, John’s uncle passed away and he found a stash of bottles in the cellar and wants to know what they are and if they will still drink well. Juliette would like to find out the value of her Port bottle even though there is no front label. Franco unearthed a “rare bottle” of Colheita in his wine rack which he purchased during a visit to Lisbon in 1972, and he wants to see what it is worth. Gordon was given a bottle of old Vintage Port by his ex-wife seventeen years ago; now he’d like to know if he should sell it and how old it really is. A Portugal-based marine archaeologist has excavated a British ship that sunk circa 1850 with a treasure trove of Port bottles; the only tell tale sign is an emblem engraved in a leaded capsule. Welcome to my world!

I have spent countless hours, days and sometimes weeks … of my personal time researching bottles for people I will never hear from again. The reward for this true love of Port activity is usually a kind “thank you” email. In reality, the satisfaction I derive from solving these Port puzzles has been worthy of the effort involved; as well as furthering my commitment to the oath of the Confraria do Vinho do Porto (brotherhood) which I take very seriously.

My return email normally starts out by requesting a very specific array of detailed digital photos from the lucky owner. It makes a big difference to be able to visualize the capsule, the shape of the bottle, the front and back labels and whether or not there is a “seal” on the bottle, etc. Often times the only piece of identification (besides the cork which is still in the bottle) is the Selo de Garantia.

To be candid, what I hoped to find out was if there was any possible way to have someone at the IVDP to contact (and I was willing to pay for the privilege) even once a month, that could help me to identify the producer and vintage of a bottle from the “code” on the Selo de Garantia?

I was informed that by utilizing the letters and numbers on the seal, a positive identification can verify which Port company the bottle came from but not necessarily the vintage. Lo and behold, I was given a direct contact that would be able to assist me in the future. All of a sudden, life seemed … just a little bit easier.

3. Casks of Port (also known as “pipes”) used to be shipped to England and elsewhere from Oporto.

Considering how many old bottles of Port were bottled in the UK, this evoked a complicated conundrum. Prior to the IVP’s regulatory change in 1974, which allowed for the bottling of Port ONLY to take place in Vila Nova de Gaia, (with newer regulations in 1986 permitting the bottling to take place in the Douro as well) … how was there real accountability for the Selo de Garantia on bottling done outside of Portugal? If you could explain the process or procedure that was followed, it would be fascinating and very much appreciated.

Response – This law changed in 1996/1997. Before that, the wine shipped in bulk and bottled abroad had no seal. Only the wines bottled and exported form Gaia had neck seals. From 1996/97 no bulk Ports are allowed to be exported form the Douro region. In 1996 the Portuguese government temporarily suspended exports of Port in bulk in order to stem the tide of counterfeiting activities which threatened the Port trade’s image.

The IVDP (Instituto do Vinho do Douro e Porto) is situated in an old and unassuming bank building in Oporto. In a governmental decree issued on the tenth of April in 1933, the Port Wine Institute was established. Its main mission is to administer quality and guarantee the origin of Port. The IVDP also has the authority to perform sensorial tests on Port wine and accept or reject the samples prior to their being bottled.

The taste testing of Port is executed by a team of seven individuals who sit down daily and must blind taste through numerous samples of black bagged Port bottles. They even get paid for this! The persons on the IVDP tasting panel painstakingly apply the results of their organoleptic (sensorial) perceptions into a computerized program.

One of the more interesting aspects of the IVDP is its responsibility for ensuring the authenticity of Port wine. That is where the Selo de Garantia (Seal of Guarantee) comes into play. The IVDP is also charged with maintaining a record of the specific Selo de Garantia registration of marks and labels, in addition to issuing Certificates of Guarantee of Port stocks in Vila Nova de Gaia and the Douro.

Don’t bother trying to figure out the “code” on the Selo labels, as you will die trying. This is a tightly guarded secret that ensures there is no funny business within the trade, but even more importantly, it makes a significant anti-fraud device on Port bottles. Of course it would not be impossible to duplicate an IVDP label, but there are way too many other areas of the world that do too little to maintain the integrity of their appellation’s bottlings.

Although many assume or associate the the Selo de Garantia actually GUARANTEES the quality within the bottle, that is definitely not the case. What it does “guarantee” is that the origin of the Port and that it is from within the confines of the demarcated Douro region.


Originally Appeared Nov 29, 2007
By | 2017-05-18T00:13:35+00:00 August 16th, 2016|Categories: History, Port Basics, Roys Blog|Tags: , |6 Comments


  1. Frederick Blais October 9, 2016 at 11:25

    Any way to find out what seal was used and between which year? This would be really helpful trying to figure out the date of bottling of old non-vintage Port.

    • Roy Hersh January 6, 2017 at 20:51

      Sorry Frederick, I am just seeing this for the first time. If you refer to which specific pattern and look of the IVP or IVDP seals went on the bottles, and which years these corresponded to, then yes that is possible to find out. Let me know if that is what you mean, otherwise, please clarify this for me.



      • Frederick Blais January 6, 2017 at 22:40

        Roy, yes it is what I meant, to know what patterns correspond to what years.

  2. H Port-er January 1, 2017 at 19:48

    Great article, as always.

    I understand they don’t want to give away the secret to the entire code, but I’d imagine it isn’t much of a mystery as to what the last two digits represent, as there is little variation with those. Can you tell us what the “04” and “05” represent on most modern Selo de Garantias? Also, when did they start applying two digits to the end of the SdG?

    Being a bit of a port nut (…although, I’m told that is redundant), I track all the SdG’s of bottles of ports I’ve tried (or have on hand.) I thought the digits after the six numbers might have something to do with the date it was bottled, because I see that a Graham’s 1970 Vintage was XX ###### 1, but then also have a Messias 1970 Vintage with an SdG of XX ###### 4 and a Churchill’s 1985 Vintage with an XX ###### 1, so that theory doesn’t seem to hold up. Any info you can pass along would be greatly appreciated.

  3. Roy Hersh January 6, 2017 at 20:56

    To be honest, it wouldn’t be that hard to follow up and find some of this out. But as a purist and one who has come across some counterfeit bottles of Port and Madeira, more in recent years than ever before … on principle, I am not going to be any help to providing this type of information that could inadvertently assist others to produce “fake Ports”. Sorry about that!

  4. H Port-er January 8, 2017 at 17:37

    I can appreciate that. I’ll look into it on our next trip to Porto.

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