Section 11 — alcoholic strength
General information on what alcoholic strength means for duty purposes, how to measure strength and what to do if there is a dispute over strength.
Alcoholic strength applies to all alcoholic products:
- entirely manufactured in the UK (sometimes referred to as domestically produced)
- imported into the UK as finished products
- imported into the UK as bulk products and bottled here
- imported into the UK as bulk products and used as ingredients in a final product made in the UK (for example, bulk wine imported and used to make a domestically produced ‘other fermented product’)
Alcoholic strength is the percentage of the volume of alcohol contained in the product to the volume of the product (inclusive of alcohol contained in it) (alcohol by volume) measured at 20°C. For duty purposes, you should round this down to one decimal place. For example, 7.59% alcohol by volume becomes 7.5% alcohol by volume.
It is mandatory for prepared products to include the strength of an alcoholic product either:
- directly on the container
- on a label attached to the container
For duty purposes the labelled strength is the strength of the alcoholic products in most cases.
If there is no label strength (for example, on a very old bottle), you must use the strength on any document relating to the container. If there is no other documentation, you should use the actual strength method.
Cask condition products, including bottle-conditioned products and any other unfinished products, will continue fermenting after removal from production premises. This will result in an increase in strength. You must account for duty on the strength at which you expect the product to be when it is consumed. This is also the strength which would be shown on the label or invoice or delivery note.
For duty purposes, the strength of the cask conditioned product is the greater one of the following:
- the final strength the product is expected to have when sold
- the strength shown on the label of the product
- the strength shown on any invoice related to the product
- the strength shown on any other document issued in relation to the product
This sub-section has force of law under regulation 3(7) of the Alcoholic Products (Excise Duty) Regulations 2023.
You must take due care to make sure the strength used to calculate the duty accurately reflects the actual strength of the product. If you have not done this, the strength will be worked out using the actual strength method.
If you’re a UK producer, you must continuously monitor and record alcohol by volume results. These will normally fall randomly on either side of the target strength which will be the declared strength. The average of your results should be close to the target strength.
Occasionally the alcohol by volume can vary, but as long as you take appropriate action to return the strength of the product to within its normal specification, due care will have been demonstrated. You must keep records of actions taken to maintain produce strength within control limits.
For imported products, you must make sure that the alcohol by volume of your products is labelled according to any relevant labelling legislation. For example, the provisions in Annex 12 of the Food Information to Consumers Regulation or (for wine of fresh grape) Article 44 of EU Regulation 2019/33 (as far as these apply in retained EU law).
Your commercial due diligence should make sure that the:
- products you import conform to legal specifications
- alcohol by volume on the label conforms to the tolerances specified in the relevant labelling rules for each product category
For cask conditioned products, in addition to these actions, you must regularly monitor and record the actual strength of a quality control sample of cask and bottled conditioned products at the expected time of consumption. This is to establish its alcoholic strength. The method and frequency of checking is up to you, but you must be able to satisfy HMRC of the accuracy of your results.
You can use any method to measure the strength of a product, if your chosen method produces a result equal to, or greater than that described in Schedule 2 of the Alcoholic Products (Excise Duty) Regulations 2023.
The actual strength method
This is a scientific measurement taken using the process described in Schedule 2 of the Alcoholic Products (Excise Duty) Regulations 2023.
The Alcoholic Products (Excise Duty) Regulations 2023, Schedule 2 specify:
- (1) The strength of spirits is to be determined —
- (a) by determining the density of spirits in the air at 20°C and taking the strength of the spirits to be the percentage of alcohol by volume corresponding to that density in the Laboratory Alcohol Table, provided that where the density of any spirits determined as mentioned falls between any two consecutive numbers in that table the strength shall be determined by linear interpolation, or
- (b) using any method that measures the strength of spirits to a level of accuracy equivalent to, or greater than, that measured by a method set out in sub-paragraph (a).
- (2) Where spirits contain any substance other than alcohol and water, the Commissioners may either —
- (a) require that the strength of the spirits be ascertained by any of the means prescribed by sub-paragraph (1) after removing from the spirits any such substance to the extent which they consider necessary by distillation or such other processes as they direct and adding water to replace the volume so removed, or
- (b) allow the strength of the spirits to be ascertained, as though they contained alcohol and water only, by either of the means prescribed in sub-paragraph (1).
- 1 (1) Except where sub-paragraph (2) applies, the strength of any alcoholic product other than spirits is to be determined —
- (a) In the following manner —
- (i) a representative sample is to be taken and, after first being cleared of sediment and gas by filtration, a definite quantity thereof by measure at the temperature of 20°C is to be distilled.
- (ii) the distillate is to be made up at the temperature of 20°C with distilled water to the original measure of the quantity before distillation.
- (iii) the strength of the distillate made up in accordance with subparagraph (b) is ascertained by determining its density in air at the temperature of 20°C by means of pycnometer and,
- (iv) the strength of alcoholic product is to be the percentage of alcohol by volume in the table entitled ‘Laboratory Alcohol Table’ which corresponds to the density determined in accordance with paragraph c) except that where the density so determined is between 2 consecutive numbers in the table aforesaid the strength shall be determined by linear interpolation.
- (b) using any method that measures the strength of alcoholic product to a level of accuracy equivalent to, or greater than, that measured by the method set out in sub-paragraph (a)
- (a) In the following manner —
- (2) Where the result ascertained by the method specified in sub-paragraph (1) above is rendered inaccurate by the presence of substances other than alcohol, that method shall be adjusted in such manner as can be approved for the purpose of producing an accurate result.
- (3) ‘Laboratory Alcohol Table’ is a table showing the relation between density at 20°C and alcoholic strength of mixtures of ethanol and water expressed as a percentage by volume at 20°C and percentage mass. Find a copy of the laboratory alcohol table for working out alcohol content.
With no or minimal laboratory facilities
If you have no or minimal laboratory facilities, you may calculate the alcoholic strength of your beer by multiplying the number of degrees by which the beer has attenuated by a factor. In order to make sure that your calculations are accurate, it is essential that the original gravity be established as soon as possible after collection and before fermentation commences, which will normally be within one hour of completion of filling the fermenting vessel.
If you add priming sugar to promote secondary fermentation you’ll need to calculate the alcoholic strength of the finished product as outlined below.
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Wait until fermentation is completed — for cask-conditioned beer this will be after secondary fermentation in the casks, then
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Measure the present gravity (also known as the specific or final gravity). Use a suitably calibrated saccharometer adjusted for the temperature of the representative sample.
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When you’ve taken your readings, calculate the alcoholic strength using the formula (original gravity – present gravity) × f = a% alcohol by volume, where:
- original gravity is the original gravity of the beer
- present gravity is the present gravity of the beer
- a is the beer’s alcoholic strength
- f is the factor connecting the change in gravity to alcoholic strength — the value of ‘f’ is not constant because the yield of alcohol is not constant for all fermentations — in lower strength beer, more of the ‘sugars’ available for fermentation are consumed in yeast reproduction than in producing alcohol.
The table below produced by the Laboratory of the Government Chemist, shows the changing value of ‘f’ depending on the alcoholic strength of the beer.
Value of factor ‘f’ for various alcoholic strengths
| (original gravity to present gravity) | % alcohol by volume | Factor |
|---|---|---|
| Up to 6.9 | Up to 0.8 | 0.125 |
| 7.0 to 10.4 | 0.8 to 1.3 | 0.126 |
| 10.5 to 17.2 | 1.3 to 2.1 | 0.127 |
| 17.3 to 26.1 | 2.2 to 3.3 | 0.128 |
| 26.2 to 36.0 | 3.3 to 4.6 | 0.129 |
| 36.1 to 46.5 | 4.6 to 6.0 | 0.130 |
| 46.6 to 57.1 | 6.0 to 7.5 | 0.131 |
| 57.2 to 67.9 | 7.5 to 9.0 | 0.132 |
| 68.0 to 78.8 | 9.0 to 10.5 | 0.133 |
| 78.9 to 89.7 | 10.5 to 12.0 | 0.134 |
| 89.8 to 100.7 | 12.0 to 13.6 | 0.135 |
The table indicates that for the majority of popular UK beers, the factor for calculating the estimated strength would lie in the range 0.129 and 0.130. For strong beers (exceeding 6% alcohol by volume), the factor would be in the range of 0.131 to 0.133. Whilst it is important that the correct value for ‘f’ is used, you should be aware that this table is primarily for your guidance. Some brewing methods and materials can affect the factor. If in any doubt you should get more advice.
Calculation of alcohol by volume when priming sugar is added to beer
If you add priming sugar at the maturation stage to promote a secondary fermentation and use the calculation method to ascertain the alcohol by volume of the finished beer, you’ll need to make calculations based on the steps outlined below.
A barrel contains 163.6 litres which comprises 161.6 litres of beer which had an original gravity of 1040 and 2 litres of added priming sugar with an original gravity of 1110. The final gravity of the mixture after secondary fermentation is 1010.
- Calculate the alcohol by volume of the fermented beer using the formula, (original gravity – present gravity) × f = a% alcohol by volume, where:
- original gravity is the original gravity of the beer
- present gravity is the present gravity of the beer (that is, final gravity after all fermentation has ceased)
- a is the alcoholic strength
- f is the factor connecting the change of gravity to alcoholic strength (1040 – 1010) × 0.129 = 3.8
- Calculate the alcohol by volume of the priming sugar using the same formula, (1110 – 1010) × 0.135 = 13.5
- Calculate the alcohol by volume of the contents of the container using the formula, (Vb × Sb) + (Vp × Sp) divided by Vm = Sm, where:
- Vb = volume of beer in the container
- Sb = alcohol by volume of the beer in the container
- Vp = volume of priming’s in the container
- Sp = alcohol by volume of priming’s in the container
- Sm = alcohol by volume of the container contents
- Vm = volume of container contents
(161.6 × 3.8) + (2.0 × 13.5) divided by 163.6 = 3.9185
Instruments must comply with schedule 2 of the Alcoholic Products (Excise Duty) Regulations 2023.
Automatic densimeters must measure density according to schedule 2 of the Alcoholic Products (Excise Duty) Regulations 2023.
The 2 main criteria are:
- the density must be directly measured as ‘density in air’ not ‘density in vacuum’ and then converted to ‘density in air’
- at the time the measurement is taken, the temperature of the liquid must be 20°C — the measurement cannot be taken at a different temperature and converted to the equivalent density at 20°C
The automatic densimeter must carry out density measurements with accuracy and precision. All of the approved densimeters have been 5-decimal places machines, and when used according to the operator’s instructions, have proved to be accurate and precise enough for our purposes.
Some machines can convert the density of a liquid to the alcoholic strength from an internal look-up table. If you select this option, the machine must use the laboratory alcohol table to convert the density in air value to an alcoholic strength.
For UK-produced products, HMRC officers will examine your testing results and records of actions taken to keep declared strength in line with actual strength. If the results have consistently fallen above your target, we’ll want to confirm that action was taken as soon as the problem was identified to bring the process back into control or to change the declared alcohol by volume.
For imported products, HMRC officers will look at your commercial due diligence. If the alcohol by volume is consistently above the declared alcohol by volume by an amount greater than the permitted tolerances, we’ll want to see an action plan to bring the production or labelling processes into alignment.
For either imported or UK produced products, if you’ve failed to take appropriate action, as assessment may be raised for the additional duty due.
HMRC officers can take samples of product which will be analysed using the method described. The analysis result will establish the actual dutiable strength of the product.
This is taken from Schedule 2 of the Alcoholic Products (Excise Duty) Regulations 2023:
- take a representative sample and, after clearing it of sediment and gas in an approved manner, a definite quantity by measure at the temperature of 20°C is make alkaline by the addition of calcium hydroxide and then distilled
- make up the distillate at the temperature of 20°C with distilled water to the original measure of the quantity before distillation
- ascertain the strength of the distillate by determining its density in air at the temperature at 20°C by means of a pycnometer
- the strength of product is the percentage of alcohol by volume in the ‘Laboratory Alcohol Table’ which corresponds to the density determined by this method — where the density falls between 2 consecutive numbers in the table the strength will be determined by linear interpolation
Where a result achieved by this method is rendered inaccurate by the presence of substances other than alcohol, that method will be adjusted for the purpose of producing an accurate result.
The following two sentences have force of law and is made under regulation 6 of the Revenue Traders (Accounts and Records) Regulations 1992.
You must keep an accurate record of the quantity and gravity of wort and wash collected.
The quantity and gravity of wort and wash should be measured using recognised industry methods.
Measuring the quantity of wort, wash and gravity for spirits producers
You should use any industry-recognised equipment, in accordance with the manufacturer’s protocol.