Appendix UNITS OF MEASUREMENT Two new systems of measurements have been introduced into Britain in the last ten years. Industry and commerce have seen the introduction of metrica­ tion to come into line with other European countries. Scientific and teaching establishments have adopted a related but not identical system called Systeme Intemationale (SI for short) illustrated in Tables A.I and A.2. Both have their place in Brewing Science as have the old systems based on the pound and the foot. Especial difficulties arise because the traditional US measures do not always correspond with the British. For instance the US gallon of water weighs 8 Ib, and the constituent eight pints one pound each. The British imperial measure, revised in Queen Anne's reign, 'metricated' the gallon of water so that it weighed 10 Ib, each pint weighing I· 25 lb. Measurements of volume such as the bushel or the barrel vary from one region to another. In this book, the barrel will be that used in England, namely 36 gallons. Filled with water this would weigh 360 lb. For rough calculation, it is convenient that the US beer barrel is rather similar to the hectolitre, exceeding it by about 17 %. The use of degrees Fahrenheit is rapidly being replaced in the UK by °C (metric) or K (SI) but not in the USA for practical brewing (Table A.3). With respect to units specifically used in brewing, certain metric units have been selected which are not in the SI, such as titres, hectotitres, metric tonnes and bars, because of their convenience. Other measurements used in brewing are becoming or have become obsolete, for instance Quarters as applied to barley (448Ib) or malt (336Ib). Methods of analysis have changed over the years so that comparisons are difficult. Elsewhere there may be no direct equivalence; a good example is measurement of extract as defined by the Institute of Brewing versus that given by the European Brewery Convention. Set out in Table A.4 are definitions of several SI and metric units plus conver­ sions of non-metric units that are relevant to brewing. Table A.5 gives details of the various systems of measuring specific gravity and extract, while Table A.6 gives equivalents of hot water extracts of malts in the old and new nomenclature. 878 APPENDIX TABLE A.I SI derived units Physical quantity Name Symbol Definition Energy joule J kg m2 S-2 Force newton N kg m S-2 = J m-1 Power watt W kg m2 S-3 = J S-1 Electrical charge coulomb C As Electrical potential difference volt V kgm2 s-3 A-1 = J A-1 S-1 Electrical resistance ohm n kg m2 s-3 A -2 = V A-1 Inductance henry H kg m 2 S-2 A -1 = V A -1 S Luminous flux lumen 1m cd sr Illumination lux Ix cd sr m-B Frequency hertz Hz S-1 where (I) m is the metr! (2) kg is the kilogram (3) s is the second (4) A is the ampere (5) cd is the candela (luminous intensity) (6) sr is the steradian (solid angle) other basic units are: (7) kelvin (K)-thermodynamic temperature and temperature interval (8) mole (mol) molecular (or atomic) weight in kg m-3 TABLE A.2 Prefixes for SI units Fraction Prefix Symbol 10-13 pica p 10-8 nano n 10-8 micro fL 10-3 milli m 10-1 centi c 10-1 deci d J01 deka da 101 hecto h lOS kilo k 10 8 mega M 10' giga G APPENDIX 879 TABLE A.3 Comparison of thermometers Showing the relative indications of the Fahrenheit, Centigrade and Reaumur thermometer scales Boiling point Freezing point Fahrenheit 2120 32 0 Centigrade 1000 00 Reaurnur 80 0 00 Conversion of thermometer degrees °C to oR, mUltiply by 4 and divide by 5. °C to of, multiply by 9, divide by 5, then add 32. oR to °C, multiply by 5 and divide by 4. OR to of, multiply by 9, divide by 4, then add 32. OF to oR, first subtract 32, then multiply by 4, and divide by 9. of to °C, first subtract 32, then multiply by S, and divide by 9. F C R F C R 230 110 88 120·2 49 39·2 221 lOS 84 118-4 48 38·4 211 100 80 116·6 47 37'6 210·2 99 79·2 114'8 46 36·8 208·4 98 78·4 113 4S 36 206·6 97 77-6 111'2 44 35.2 204-8 96 76·8 109-4 43 34'4 203 95 76 107-6 42 33-6 201·2 94 75·2 105'8 41 32·8 199·4 93 74·4 104 40 32 197·6 92 73-6 102·2 39 31·2 195-8 91 72-8 100'4 38 30·4 194 90 12 98·6 37 29·6 192-2 89 71·2 96'8 36 28·8 190·4 88 70·4 95 35 18 188·6 87 69·6 93·2 34 27·2 186·8 86 68'8 91·4 33 26·4 185 85 68 89.6 32 25·6 183-2 84 67-2 87-8 31 24·8 181-4 83 66·4 86 30 24 179·6 82 65·6 84·2 29 23-2 177-8 81 64·8 82·4 28 22-4 176 80 64 80·6 27 21·6 174·2 79 63-2 78·8 26 20·8 172-4 78 62-4 77 25 20 170·6 77 61-6 75·2 24 19·2 168·8 76 60·8 73-4 23 18·4 167 75 60 71-6 22 17-6 165'2 74 59'2 69'8 21 16'8 16H 73 58·4 68 20 16 161-6 72 57-6 66·2 19 15·2 159·8 71 56·8 64·4 18 1404 158 70 56 62·6 17 13-6 156·2 69 55·2 60'8 16 12·8 154·4 68 54·4 59 15 II 152-6 67 53-6 57-2 14 11'2 150·8 66 52-8 55-4 13 10·4 149 65 52 53-6 12 9·6 147-2 64 51·2 51·8 11 8·8 145-4 63 50·4 50 10 8 143·6 62 49-6 48·2 9 7·2 141·8 61 48·8 46·4 8 6·4 140 60 48 44-6 7 5.6 138'2 59 47-2 42-8 6 4·8 136·4 58 46·4 41 5 4 134·6 57 45·6 39·2 4 3·2 132-8 56 44·8 37-4 3 H 131 55 44 35·6 2 1-6 129·2 54 43·2 33-8 I 0'8 127-4 53 42-4 32 0 0 125-6 52 41-6 30'2 -I -0,8 123-8 51 40·8 23 -5 -4 112 50 40 14 -10 -8 880 APPENDIX TABLE A.4 Conversions METRIC SYSTEM m = 1·0936 yard = 3'2808 ft; em = 0'3937 in; hectare = 2·471 acre; m2 = 10'764 ft2; cm2 = 0'1550 in2; rna = 1000 dm3 (or litre) = 33·315 ft3 = 61024 ina; hi = 100 dma (or litre) = 21·998 gal (British) = 26·418 gal (US) = 0·6111 barrel (British) = 0·8387 barrel (US) = 0·8522 beer barrel (US); litre = 35·196 ft. oz (British) = 33-815 ft. oz (US); tonne = 1000 kg = short ton = 0·9842 long ton = 2204·6 Ib = 10 doppelzentner = 20 zentner; zenter = 50 kg = 0·984 cwt = 1l0·231Ib; g = 0'035270z = 15·432 grain. BRITISH MEASURES yard = 3 ft = 36 in = 0·9144 m; in = 2.540 cm = 1000 thou (thousandth of an inch); thou = 25·4 micron or micrometre; acre = 4840 yd2 = 0·4047 hectare; ydB = 0·8361 m2; ft2 = 9·290 dm2 ; in2 = 6·452 em2 ; yd3 = 0·7646 m3 ; ft3 = 28·317 dm3; in 3 = 16·387 cm3; ton (long) = 20 cwt = 2240 lb = 1016 kg; lb = 160z = 256 dram = 7000 grains = 0·45359 kg; oz = 28·35 g; grain = 64·80 mg; gal = 160 ft. oz = 8 pints = 1·201 gal (US) = 4· 546 litre = 0·1605 ft. 3 ; pint = 0·5682 litre; fl. oz = 28·412 ml; butt = 2 hogshead = 3 barrel = 108 gal = 4·9096 hi; brl = 2 kilderkin = 4 firkin = 36 gal = 1·6365 hi = 1·4 brl beer (US). us MEASURES beer brl = 31 gal (US) = 25-81 gal (British) = 1'1734 hi = O· 717 brl British; standard brl = 31·5 gal (US) = 26·23 gal (British) = 1-1924 hi = 0·729 brl British; gal = 8 pint = 128 ft. oz = 3'7853 litre = 0'8327 gal British = 231'0 ina. BARLEY AND MALT MEASURES Britain and South Africa: Barley bushel = 56lb = 25·401 kg; Barley quarter = 448 Ib = 203·209 kg; Malt bushel = 42lb = 19·051 kg; Malt quarter = 3361b = 152·407 kg; Australia and New Zealand: Barley bushel = 50 Ib; Malt bushel = 40 Ib; US and Canada: Barley bushel = 481b; Malt bushel = 341b; USEFUL DATA 1 kcal = 4·186 kJ = 3-968 BTU = 1·1628 Wh = 3088 ft Ib; BTU = 1·055 kJ = 0·252 kcal = 0·2931 Wh = 778·2 ft Ib; Wh = 3-6 kJ = 0·860 kcal = 3-412 BTU = 2655 ft Ib; therm = 105·506 MJ = 29·307 kWh; standard ton refrigeration per 24 hr = 12000 BTU/hr = 3024 kcal/hr; atm = bar = 14·70Ib/in2 = 750.1 mm Hg = 106 Nm-2 ; lb in-2 = 6894·76 Nm-2 = 0.06895 bar = 703 kg m-2 = 27·7 inches water; lb/gal (British) = 99·76 gil; lb/gal (US) = 119·8 gil; lb/brl (British) = 3.336 gil; lb/brl (US) = 3-865 gfl; grain/gal (British) = 14·25 mg/I; grain/gal (US) = 17'12 mg/I; CO.