Here’s a link to the latest news story regarding the 95% pint.

Effectively, Samuel Smith’s Brewery are asking their bar staff to commit criminal offences or to face the sack.

According to the British Beer & Pub Assosiation guidance, customers should expect a MINIMUM of 95% in a pint brim measure. If Samuel Smith’s expect an AVERAGE of 95%, then every measure that they consider to be overmeasure (i.e. over 95%) must be balanced by an corresponding short measure of less than 95%.

I assume that Samuel Smith’s Brewery are amongst the supporters of retaining the 95% imperial draught pint. One wonders if this support is conditional upon them being allowed to continue to exploit these tolerances to achieve systematic corporate short measure?

On the contrary, manufacturers of 1-litre glasses currently cannot sell such glasses for draught beer in the UK. However, if they added a CE-approved 1-pint line they could then sell these glasses to UK pubs that might want them for special events such as Oktoberfest celebrations, or other themed occasions – so long as the litre of beer served in them was declared as “1 pint”.

i.e. Would it be legal to serve a “pint” of draught beer in a litre glass that had a CE approved 1-pint line marker at the 1-pint level, but fill the glass past the 1-pint line and up to the 1-litre mark? So long as it was sold as being a pint (albeit a very generous one) would this be a way of legally serving a litre of beer?

The issue I was attempting to investigate was that the lined glass should ensure that at least a full liquid measure was provided regardless of any head. The benefit of the lined glass is that the head is contained unlike the brim measure where a full measure could only be available without a head. My observations indicated that lined glasses appeared to measure 95% to the line rather than full measure.

I would be happy to attend a test session where my domestic kitchen experiment could be repeated and enhanced to minimise any errors in line with the issues detailed by Ken Cooper. Ideally in the presence of a trading standards officer who could compare results using the suitably calibrated equipment they would normally use when checking measures in a public house.

“I was explaining to my grandsons that 100 grams of water occupy 100 cc and using the CAMRA tankard tried the same experiment of 1/2 pint weighs 10 oz or measures 10 fluid ounces.”

The above would only be correct under certain strictly defined conditions. If you are trying to accurately determine volume by gravimetric methods, temperature and barometric pressure will have an influence. When you are working really accurately, you even have to take account of the cubic coefficient of expansion of the glass measure under test. This sort of level of accuracy is not required for testing measures in use for trade, but there are many other factors which will introduce uncertainty into your measurements.

“We were using an electronic digital scale”

How do you know that the scale was reading correctly? Had the scale been calibrated using weights traceable to National Standards? Was the scale capable of displaying both imperial and metric units? What was the capacity of the scale? What resolution did the scale work to (1/8 oz?, 1/16 oz?, 1 g?, 2 g?)

“and for calibration an ‘old style’ 1/2 pint crown glass filled to the brim confirmed it contained 10 fl oz.”

How did you ensure that your reference measure was correctly filled to the brim? Surface tension will allow you to overfill a brim measure. How did you overcome this?

An old style ½ pint crown stamped glass could have contained any amount between ½ pint and ½ pint plus 20 ml (approx.. 284 ml and 304 ml) at the time it was stamped. As such, when used as a delivery measure (even if it was correctly filled), it is likely to deliver slightly over ½ pint

“The festival tankard filled with a 10 fl oz measure of water indicated a level about 1/8 inch above the ’1/2 pint to the line’ mark.”

How did you measure this? There are 4 options:

1) top of meniscus to top of line,
2) top of meniscus to bottom of line
3) bottom of meniscus to top of line
4) bottom of meniscus to bottom of line

Only one of these 4 methods will produce a correct result.

Also, was the measure under test wet or dry? Again, only one condition will produce a correct result

“Using a straw to remove 1/2 fl oz moved the level to the marked line.”

Without taking into account any of the other errors that may have been introduced, I’m not surprised that a brim measure which can legally contain any amount between approx. 284 ml and 304 ml will deliver an amount that may be slightly above a line which may legally be marked at any point between approx. 277 ml and 291 ml on a line measure.

This is an obvious consequence of the fact that a brim measure has an error allowance in excess only (to make space for a head on the pint) while a line measure has an error allowance in excess or deficiency as the head will be above the line.

“For greater accuracy I have subsequently repeated using metric units and on testing a 175 ml line marked wine glass it measured 166 ml”

What standard did you use to measure your 175 ml? Was this done on the same scale you used to test ½ pint glasses?

“IN ALL CASES THE MEASURE TO THE LINE WAS 95% = 5% SHORT MEASURE”

Assuming that the measure was CE marked, this is perfectly acceptable for any measure of 200 ml or less. Above 200ml, the error allowance gradually decreases. At 500ml, it would be 3.5% and at 1 litre it would be 3%

However the apparent sample of 2 glasses (and potentially inaccurate methods used) hardly demonstrates that every measure is manufactured to exploit the allowable tolerances. No manufacturer is going to try to make glasses that are all on the limit of the tolerance – he’s going to use these tolerances to try and minimize his own manufacturing costs – if he is manufacturing lined glasses with a nominal capacity of 200 ml, he is going to be happier with a batch of 1000 glasses that average 200 ml +/- 8 ml than he is with having to destroy or rework around 250 glasses from a batch that average 192 ml +/- 4 ml

“Research into the weights and measures law confirms that drinks may be dispensed 5% under or 1% over measure. So it would appear the manufacturers of lined glasses use 95% when marking measures to the line – but still indicating a full measure!”

Not correct. I’m not sure where you get your 1% over figure from – there’s no such allowance as far as I’m aware.

A code of practice (see below) says that 5% short is acceptable for a draught “pint” of beer. This relates to the amount of beer delivered, not to the error allowance on the measure used. This practice is only regarded as acceptable to sales of draught beer, however – not wine or spirits

What the actual law says is that the head is part of a pint (Marshall v Searles and Dean v Scottish and Newcastle are the relevant cases). It is accepted that the head is a mixture of liquid and froth.

The code of practice states:
“5. When dispensing beer with a head into a brim measure glass the head must reach the brim or above it to ensure that the quantity of beer (liquid and head) dispensed is at least a pint or half a pint. As the head collapses the small proportion of liquid it contains will fall into the rest of the beer and the gas will disperse into the atmosphere. When the head has totally collapsed the amount of liquid may be less than a pint or half pint. The deficiency will depend on the size of the head and the type of beer. The Brewers and Licensed Retailers Association and the Retail Organisations listed have agreed that a head of froth is excessive and unreasonable if the measure of draught beer does not contain a minimum of 95% liquid after the collapse of the head. They recommend as strongly as possible that all licensees follow this principle. The recommendation that the measure of draught beer should contain a minimum of 95% liquid applies whether or not a top-up has been requested.

This is far less relevant when a line measure is used, as vast majority of the head will be above the line, so it is far less likely that short measure will be delivered.

“In my opinion the lined glass seems to have perpetuated short measures still within trading standard and apparently also adopted by CAMRA. I may not be renewing my CAMRA membership”

I would have to disagree with your opinion. Your methods of testing the small sample of measures you refer to above would appear to be seriously flawed. I would prefer to trust the CE mark or stamp applied by the authorised verifier.

In addition, it has long been accepted that line measures provide a larger measure than the equivalent brim measure when used to deliver beer. Why else would publicans be so reluctant to adopt them?

As a life long supporter of Real Ale, I was pleased when my son-in-law paid for a CAMRA membership at Christmas. Taking advantage of free admission as CAMRA members we attended the recent Northern Beer Fest in Manchester. We bought the festival 1/2 pint tankard marked both 1/3 & 1/2 pint to the line and spent a great afternoon sampling a wide range of real ale

Next week I was explaining to my grandsons that 100grams of water occupy 100cc and using the CAMRA tankard tried the same experiment of 1/2 pint weighs 10oz or measures 10 fluid ounces. We were using an electronic digital scale and for calibration an ‘old style’ 1/2 pint crown glass filled to the brim confirmed it contained 10 fl oz

The festival tankard filled with a 10 fl oz measure of water indicated a level about 1/8 inch above the ’1/2 pint to the line’ mark. Using a straw to remove 1/2 fl oz moved the level to the marked line. For greater accuracy I have subsequently repeated using metric units and on testing a 175ml line marked wine glass it measured 166ml

IN ALL CASES THE MEASURE TO THE LINE WAS 95% = 5% SHORT MEASURE

Research into the weights & measures law confirms that drinks may be dispensed 5% under or 1% over measure. So it would appear the manufacturers of lined glasses use 95% when marking measures to the line – but still indicating a full measure!

Returning to CAMRA who strongly support full measures – on their festival website they promote the use of their lined glasses with the statement that it was saving us money by giving a full pint rather than the usual pub short measure
See http://www.alefestival.org.uk/winterales/ and the CAMRA section on full pints which states ‘ There is also evidence that some pub operators have adopted a deliberate policy of serving short measurers to get 5% more out of every barrel. If we did this at National Winter Ales Festival you would be overcharged by 15 pence on a £2.00 pint’.

In my opinion the lined glass seems to have perpetuated short measures still within trading standard and apparently also adopted by CAMRA.

I may not be renewing my CAMRA membership

The Capacity Measures (Intoxicating Liquor) Regulations 1988 gave an allowance (in excess or deficiency) of 17 ml for pint line measures. This had the effect of making it legal to mark the crown stamp & a “pint to line” marking on any line measure which contained any amount between 551.3 ml and 585.3 ml when tested with water and filled to the line (figures rounded to 0.1 ml)

Similarly, the Measuring Instruments (Capacity Serving Measures) Regulations 2006 currently give an allowance (in excess or deficiency) of 5 ml + 2.5% for pint line measures. This has the effect of making it legal to mark the CE mark & a “pint to line” marking on any line measure which contains any amount between 549.1 ml and 587.5 ml when tested with water and filled to the line (figures again rounded to 0.1 ml)

So, in other words, the tolerance window was identical, but distributed around the line on a line measure instead of in excess only as in a brim measure.

I’m not aware of any efforts to exploit the tolerance by the glass manufacturers. I don’t know the verification procedures at the large UK glass manufacturers when they were still in business, but on the few occasions I verified pint brim measures, the easiest way was to make sure it didn’t overflow when a pint was poured in, and that it did overflow when you added a further 34 ml. As such, the individual errors were not worked out.

A manufacturer who wants maximum tolerance would set his target at about 585 mL, but with tighter tolerance control, might choose any target in the range 570 – 600 mL. Is a manufacturer allowed to advise his customer (the pub owner) of his actual average capacity? Clearly, the pub owner would prefer glasses that average toward the low end, without imposing such tight tolerances that the cost has to be significantly increased. Lower cost glasses would tend towards the middle of the range.

I can envision optimization around a minus zero, plus “x” tolerance where the customer wants x small and the manufacturer wants it large, and they haggle over a cost function. For the pub owner, the question is “how much beer will the glass serve before it is discarded” and what savings on beer would smaller x provide.