I test rums with a hydrometer and include the info in my rum reviews. The objective of this is not to be critical of any specific rum/brand, but to put information into the public domain regarding additives in rums to assist consumers in knowing what is added to their drinks and therefore whether or not the price tag of a bottle is justified. It is not a scientific test carried out in a laboratory nor does it definitively prove that additives in rums exist.

I followed Johnny Drejer’s guidelines, as stated on his Drecon web site.

UPDATED: January 9th 2021

Brand/Bottler	Rum	Label ABV	Hydro ABV	Est. Sugar
970 Rum Agricola Da Madeira	15yo Cask Strength	50.9%	51%	0-5g
970 Rum Agricola Da Madeira	Madeira Wine Cask Finish	51.7%	51-2%	0-5g
970 Rum Agricola Da Madeira	Single Cask Edition Cask 20 2017	52.8%	53%	0-5g
A1710	Nuée Ardente	44.7%	45%	0-5g
Ableforth’s	Rumbullion Spirit Drink	42.6%	30.8%	43g
Ableforth’s	Rumbullion Navy Strength	57%	34%	103g
Adelphi	Hampden 15yo	54.3%	54.3%	0-5g
Admiral Rodney	Officer’s Release No.1 Port Finish	45%	45%	0-5g
Alnwick	Golden Spiced Rum	40%	33%	26g
Antigua Distillery	Velier “Heavy” Rum	66%	66%	0-5g
Appleton	12yo “Rare Blend” Rum	43%	43%	0-5g
Appleton	EXCLUSIVE Rum	43%	43%	0-5g
Appleton	“Joy” 25yo	45%	45%	0-5g
Appleton	30 Year Old (2nd Edition)	45%	45%	0-5g
Appleton	Master Blenders’ Legacy (MBL)	43%	43%	0-5g
Bacardi	Facundo Eximo 10 Year Old	40%	37%	12g
Bacardi	Gran Reserva Limitada Rum	40%	40%	0-5g
Bayou	Gold	40%	36.8%	12g
BBR	18 Year Old Caroni Rum	46%	46%	0-5g
Blackadder	Barbados Foursquare 2004-10yo	64.4%	64%	0-5g
Black Tot	Finest Caribbean	46.2%	46%	0-5g
Butterbird	Rum	46%	46%	0-5g
Cadenhead’s	GMBV Bellevue Distillery 17yo	54.3%	54%	0-5g
Cane & Bean	1870	40%	40%	0-5g
Cane Island	Barbados	40%	40%	0-5g
Cane Island	Jamaica	40%	40%	0-5g
Chairman’s Reserve	Legacy	43%	43%	0-5g
Chairman’s Reserve	Original	40%	40%	0–5g
Chairman’s Reserve	White	40%	40%	0-5g
Compagnie des Indes	Barbados Multi Distilleries 20yo	45%	45%	0-5g
Compagnie des Indes	Foursquare 16yo	45%	45%	0-5g
Compagnie des Indes	Hampden 15yo	43%	43%	0-5g
Compagnie des Indes	Kaiman	46%	46%	0-5g
Compagnie des Indes	St Lucia 13yo	43%	43%	0-5g
Conde de Cuba	15 Anos Rum	38%	38%	0-5g
Domaine de Courcelles	1972 (Rhumhouse Edition)	54%	54%	0-5g
Don Q	Finished in Sherry Casks	41%	41%	0-5g
Don Q	Gran Añejo Rum	40%	40%	0-5g
Don Q	Single Barrel 2005	40%	40%	0-5g
Don Q	Sweet Vermouth Cask “Finish”	40%	40%	0-5g
El Dorado	“Rare” Collection Enmore 1993	56.5%	56.5%	0-5g
El Dorado	“Rare” Collection Port Mourant 1999	61.4%	61.4%	0-5g
El Dorado	“Rare” Collection Versailles 2002	63%	61%	8g
El Dorado	12yo	40%	30%	35g
El Dorado	15yo (Special Reserve)	43%	33.5%	36.5g
El Dorado	15yo MADEIRA DRY Finish	43%	40.5%	10g
El Dorado	15yo MADEIRA SWEET Finish	43%	40.7%	10g
El Dorado	15yo RUBY PORT Finish	43%	40.5%	10g
El Dorado	15yo SAUTERNES Finish	43%	42%	4g
El Dorado	15yo WHITE PORT Finish	43%	40.6%	10g
El Dorado	15yo RED WINE Finish	43%	41%	8g
El Dorado	21yo	43%	34.5%	33g
El Dorado	EHP (Single Barrel)	40%	40%	0-5g
El Dorado	ICBU (Single Barrel)	40%	38%	8g
El Dorado	PM (Single Barrel)	40%	40%	0-5g
El Dorado	Enmore (Ruby Port) 2003 15yo	62.1%	59%	17g
El Dorado	Enmore (Sauternes) 2003 15yo	62.3%	58%	22g
El Dorado	Enmore 2006 12yo	40%	38%	8g
English Spirit Distillery	Old Salt Rum	42%	41.5%	0-5g
English Spirit Distillery	St. Piran’s	42%	42%	0-5g
Fair	11 Year Old Rum	50.7%	51%	0-5g
Flor de Caña	25	40%	40%	0-5g
Foursquare	1985 Distilled	43%	43%	0-5g
Foursquare	2006	62%	62%	0-5g
Foursquare	ECS I 1998	40%	40%	0-5g
Foursquare	ECS III 2004	59%	59%	0-5g
Foursquare	ECS V Criterion	56%	56%	0-5g
Foursquare	ECS VI 2005	59%	59%	0-5g
Foursquare	ECS VII Dominus	56%	56%	0-5g
Foursquare	ECS VIII Premise	46%	46%	0-5g
Foursquare	ECS XII Nobiliary	62%	62%	0-5g
Foursquare	ECS XIII 2008	60%	60%	0-5g
Foursquare	ECS XIV Détente (Detente)	51%	51%	05g
Foursquare	2005 Milano Rum Festival	57%	57%	0-5g
Foursquare	Plenipotenziario	60%	60%	0-5g
Foursquare	Private Cask Selection TWE Diadem	60%	60%	0-5g
Foursquare	Private Cask Selection V and B	48%	48%	0-5g
Foursquare	Rum Sixty Six Cask Strength (Old Edition)	59%	59%	0-5g
Foursquare	Triptych	56%	56%	0-5g
Havana Club	15yo	40%	40%	0-5g
Havana Club	Edicion A	40%	40%	0-5g
Havana Club	Edicion B	40%	40%	0-5g
Havana Club	Seleccion de Maestros	45%	45%	0-5g
Kill Devil	Guyana, Enmore 24 YO	46%	46%	0-5g
Kill Devil	Hampden 16yo	46%	46%	0-5g
Kintra	Foursquare 14Y	57.7%	57-8%	0-5g
Kintra	Worthy Park 10y	61.8%	62%	0-5g
La Hechicera	Banana Infused Rum	41%	20%	68g
La Hechicera	Muscat Cask Finish	43%	43%	0-5g
La Hechicera	Rum	40%	40%	0-5g
Liverpool	Liverpool Rum	43%	41.9%	4g
Mezan	Trinidad 2007	46%	46%	0-5g
Mhoba	Select Agricole Aged 2 1/2yo	43%	43%	0-5g
Mount Gay	1703 (Original)	43%	43%	0-5g
Mount Gay	Black Barrel (Original)	43%	43%	0-5g
Mount Gay	Peat Smoke Expression Rum	57%	57%	0-5g
Mount Gay	XO Triple Cask (2020 Edition)	43%	43%	0-5g
Neisson	Cuvée du 3ème Millenaire	45%	45%	0-5g
Neisson	Profil 105	54.2%	54%	0-5g
Neptune Rum	3yo	40%	40%	0-5g
New Dawn Traders	New Dawn Rum	42%	40%	8g
Plantation	Extrême No. 2: Fiji Islands 16yo	61.1%	61%	0-5g
Plantation	Extrême No. 2: Guyana 18yo	59.7%	60%	0-5g
Plantation	Fiji 2009	44.8%	45%	0-5g
Plantation	Guatemala & Belize	42%	36%	23g
Plantation	Haiti XO	41%	37%	16g
Plantation	Isle of Fiji	40%	36%	16g
Plantation	Jamaica & Guyana 19yo	42%	37%	12g
Plantation	M&S Jamaican Rum	42%	38.2%	16g
Plantation	O.F.T.D	69%	69%	0-5g
Plantation	Peru 2004	43.5%	42.5%	7g
Plantation	Xaymaca Special Dry Rum	43%	43%	0-5g
Prichard’s	Private Stock	45%	45%	0-5g
Rhum Depaz	XO	45%	45%	0-5g
Rhum JM	Armagnac Finish	41.5%	41-2%	0-5g
Ron Abuelo	Centuria	40%	34%	22g
Ron Abuelo	XV: Cask Finish Oloroso Sherry	40%	27%	44g
Ron Abuelo	XV: Cask Finish Tawny Port	40%	28.6%	39.5g
Ron Abuelo	XV: Cask Finish Napoleon Cognac	40%	29.8%	35g
Ron Barcelo	30th Anniversary	43%	38%	20g
Ron Centenario	30th Anniversary	40%	24%	53g
Ron Centenario	Edicion Limitada 30	40%	27%	44g
Ron Colón	Salvadoreño Rum	55.5%	55-56%	0-5g
Ron Los Valientes	Añejo Reserva Especial	43%	43%	0-5g
Ron Zacapa	23	40%	36.6%	14g
Ron Zacapa	XO	40%	34%	22g
Ron Zacapa	Royal	45%	38%	29g
Rum Cask	Hampden Estate Single Cask 17yo	63.2%	63%	0-5g
Rum Diary Bar	Spiced Cherry	44%	34%	39g
Rum Diary Bar	Royal Fortune	57%	53.5%	18.5g
Rum Malecon	Rare Proof 18	51.7%	46%	25g
Rum Malecon	Rare Proof 20	48.4%	42%	29g
Rum Malecon	Reserva Imperial 21 Years Old	40%	38%	8g
Rum Malecon	Reserva Imperial 25 Years Old	40%	38%	8g
Ryoma	7yo	40%	40%	0-5g
Saint Lucia Distilleries	1931 First Edition	43%	43%	0-5g
Saint Lucia Distilleries	1931 Second Edition	43%	43%	0-5g
Saint Lucia Distilleries	1931 Third Edition	43%	39%	16g
Saint Lucia Distilleries	1931 Fourth Edition	43%	43%	0-5g
Saint Lucia Distilleries	1931 Fifth Edition	46%	46%	0-5g
Saint Lucia Distilleries	1931 Sixth Edition	46%	46%	0-5g
Saint Lucia Distilleries	Chairman’s Reserve White	40%	40%	0-5g
Sang Som	Rum	40%	37%	12g
Santa Teresa	1796	40%	40%	0-5g
SBS	Barbados 2008 Rum (Foursquare)	55%	55%	0-5g
Seven Fathoms	Rum	40%	40%	0-5g
Sister Isles	Reserva Rhum	40%	37%	12g
SMWS	R1.4 “Gets the Juices Flowing”	66.2%	66.2%	0-5g
SMWS	R6.1 “Spice at the Races”	57.3%	57-8%	0-5g
SMWS	R6.2 “My Thai Spice in Bimshire”	56.8%	57%	0-5g
SMWS	R7.1 “Welcome to Jamrock”	54%	54%	0-5g
SMWS	R8.1: “A Tot In The Workshop”	57.5%	57.5%	0-5g
SMWS	R8.2: “The Hunt Master Before Lunch”	57.5%	57.5%	0-5g
SMWS	R8.3 “Fruit and Nut Case”	55%	55%	0-5g
SMWS	R8.4: “Campfire in Nicaragua”	57.5%	57.5%	0-5g
SMWS	R9.1: “Music For Rockers of Rum”	61.8%	60%	10g
SMWS	R9.2 “Paddington Bear’s First Sip”	62%	62%	0-5g
SMWS	R11.1: “Spicy Sweet Goodness”	57.5%	57.5%	0-5g
SMWS	R11.2 “Absolutely Fabulous”	57.5%	57.5%	0-5g
Sparrow’s	Premium Aged Rum	40%	40%	0-5g
St. Abbs	Captain’s Table XO	40%	38%	8g
St. Abbs	White	40%	40%	0-5g
St. Nicholas Abbey	5yo	40%	40%	0-5g
St. Nicholas Abbey	5yo Cask Strength	60%	60%	0-5g
St. Nicholas Abbey	8yo	40%	40%	0-5g
St. Nicholas Abbey	10yo	40%	40%	0-5g
St. Nicholas Abbey	12yo	40%	40%	0-5g
St. Nicholas Abbey	15yo	40%	40%	0-5g
St. Nicholas Abbey	18yo	40%	40%	0-5g
St. Nicholas Abbey	20yo	40%	40%	0-5g
The Duchess	Martinique 15yo	61%	61%	0-5g
The Duchess	Barbados 13yo (Foursquare)	59%	59%	0-5g
Ultimatum	Foursquare Rum 3yo	46%	46%	0-5g
Velier	Royal Navy Very Old Rum	57.18%	57-8%	0-5g
Virgin Holiday Spirit	Rum	40%	40%	0-5g
Whisky Broker	16yo Rum at WIRD	57.6%	57-8%	0-5g
William Hinton	3yo	40%	36.4%	0-5g
William Hinton	Gold	40%	40%	0-5g
William Hinton	Lisbon Fortified Wine Cask	42%	42%	0-5g
William Hinton	Madeira Cask Finish	42%	39.6%	10g
William Hinton	Maldita Beer Cask	42%	42%	0-5g
William Hinton	Portuguese Fortified Wine Cask Finish	42%	42%	0-5g
William Hinton	Whisky Cask Finish	42%	42%	0-5g
William Hinton	White	40%	40%	0-5g
Worthy Park	Series #2 Oloroso Cask Finish	59%	59%	0-5g
Worthy Park	Series #3 Sherry Cask	57%	57%	0-5g
Worthy Park	Series #4 Madeira Cask	58%	58%	0-5g
Worthy Park	Series #5 Port Cask	56%	56%	0-5g
Worthy Park	Series ??? Virgin Oak	55%	55%	0-5g
Worthy Park	Single Estate Reserve	45%	45%	0-5g

I would also like to say thanks to Wes who originally suggested to me to get a hydrometer for testing rums, back in 2016.

Here are some links to other hydrometer tests:

Wes at FRP
Johnny at Drecon
Capn Jimbo