Hop Bittering Aroma Percentage

[roverfj1200]

Hi fellas

I have just started extract brewing. I would like to know if there is a percentage of bitterness that is a starting point.

I will try to explain

If I boil for say 50min and that hop gives me 25 IBU and my 20 or 15 min hop addition adds say 2 IBU to the total IBU

Is there a rough guide to how much the later hop bitterness should add to the total bitterness..

Also I have used a 10min 10g Golden cluster boil for my K&K and find this almost right for my taste. Would say 5g at 20 min and 5g at 10 min be a better option for over all hop flavour and aroma than say splitting the time at 15 min.

Cheers and thanks..

 

[Tony M]

Tinseth tables will tell you all.


Utilization Table
Decimal Alpha Acid Utilization vs. Boil Time and Wort Original Gravity

Boil Original Gravity
Time 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.100 1.110 1.120 1.130
(min)
0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
3 0.034 0.031 0.029 0.026 0.024 0.022 0.020 0.018 0.017 0.015 0.014
6 0.065 0.059 0.054 0.049 0.045 0.041 0.038 0.035 0.032 0.029 0.026
9 0.092 0.084 0.077 0.070 0.064 0.059 0.054 0.049 0.045 0.041 0.037
12 0.116 0.106 0.097 0.088 0.081 0.074 0.068 0.062 0.056 0.052 0.047
15 0.137 0.125 0.114 0.105 0.096 0.087 0.080 0.073 0.067 0.061 0.056
18 0.156 0.142 0.130 0.119 0.109 0.099 0.091 0.083 0.076 0.069 0.063
21 0.173 0.158 0.144 0.132 0.120 0.110 0.101 0.092 0.084 0.077 0.070
24 0.187 0.171 0.157 0.143 0.131 0.120 0.109 0.100 0.091 0.083 0.076
27 0.201 0.183 0.168 0.153 0.140 0.128 0.117 0.107 0.098 0.089 0.082
30 0.212 0.194 0.177 0.162 0.148 0.135 0.124 0.113 0.103 0.094 0.086
33 0.223 0.203 0.186 0.170 0.155 0.142 0.130 0.119 0.108 0.099 0.091
36 0.232 0.212 0.194 0.177 0.162 0.148 0.135 0.124 0.113 0.103 0.094
39 0.240 0.219 0.200 0.183 0.167 0.153 0.140 0.128 0.117 0.107 0.098
42 0.247 0.226 0.206 0.189 0.172 0.158 0.144 0.132 0.120 0.110 0.101
45 0.253 0.232 0.212 0.194 0.177 0.162 0.148 0.135 0.123 0.113 0.103
48 0.259 0.237 0.216 0.198 0.181 0.165 0.151 0.138 0.126 0.115 0.105
51 0.264 0.241 0.221 0.202 0.184 0.169 0.154 0.141 0.129 0.118 0.108
54 0.269 0.246 0.224 0.205 0.188 0.171 0.157 0.143 0.131 0.120 0.109
57 0.273 0.249 0.228 0.208 0.190 0.174 0.159 0.145 0.133 0.121 0.111
60 0.276 0.252 0.231 0.211 0.193 0.176 0.161 0.147 0.135 0.123 0.112
70 0.285 0.261 0.238 0.218 0.199 0.182 0.166 0.152 0.139 0.127 0.116
80 0.291 0.266 0.243 0.222 0.203 0.186 0.170 0.155 0.142 0.130 0.119
90 0.295 0.270 0.247 0.226 0.206 0.188 0.172 0.157 0.144 0.132 0.120
120 0.301 0.275 0.252 0.230 0.210 0.192 0.176 0.161 0.147 0.134 0.123

edit. The tables didnt copy too well but if you search, you will find them

 

[roverfj1200]

Thanks Tony
not quite what I am asking.

If I say a ratio between early and late hop additions does that make more sense

 

[Tony M]

If I boil for say 50min and that hop gives me 25 IBU and my 20 or 15 min hop addition adds say 2 IBU to the total IBU

Is there a rough guide to how much the later hop bitterness should add to the total bitterness..

Okay, there are some sums to do in conjunction with those tables.

Hop weight (gm.) = (Target IBU X Volume of wort at end of boil.) divided by (10 X Alpha Acid of hops X Utilisation (from the tables)).
So if you want a beer with 27 IBU of bitterness and a little hop flavour, go to the tables and look up the utilisation for your cooking times and your original gravity. For a 1.050 wort the numbers would be 0.221 for 50 minutes boil and 0.114 for 15 minutes. If your bittering hops are 11%AA and flavour hops 4%AA you can calculate the quantities as follows.

bittering hop wt = (25ibu X 21litre) / (10 X 11aa X 0.221) = 21 grams.
flavour hop wt. = (2 ibu X 21litre) / (10 X 4 aa X 0.114) = 9 grams

If you want more hop flavour and the same bitterness. you can juggle the numbers in that formula to give your required ratio.