I have read that whole hops impart less bitterness than pellet hops by weight. I have used pellet hops for all of my brews thus far. I have a recipe that I am happy with, and I want to switch to using whole hops. Is there some reliable conversion between appropriate weights for whole hops vs. pellet hops? Is it perhaps 20% more — or some other number?
1 Answer
You will get more utilization from pellet hops since they are pulverized, giving them more contact with the wort during the boil. However there isn't a hard and fast conversion rate, since there are a lot of variables with hops. Brew Dudes suggests you get 10-25% better utilization with pellet hops, and 10% is the typical number I've heard, so working off of that, you can use about 10% more whole hops to make up the difference.
I'm not sure what scale you are working on, but instead of buying another ounce of hops to get an extra .2-.4 ounces, I might just increase the boil time for the existing hops to bump the IBUs.
I'd say just experiment with slightly more hops or a slightly longer boil until you get something that tastes about right, but unless you have a sensitive palate you may not even notice the difference.
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1+ 1: Just to add to this, although the utilisation is higher you don't get more acids from pellets. It is just easier/quicker to achieve bitterness levels because of the increased surface area of the crushed and pelletised hops. A longer boil, for cones, should start to close the gap between bitterness from cones or pellets. Most bittering takes place in the first 90 minutes, and unless you are adding aroma hops at the end of the boil, you wont find many more bitterness units added between 90 - 120 mins.– iWeaselCommented Jun 29, 2011 at 6:48
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Thanks for the clarification, iWeasel. I often use the Hop Burst technique (getting most of my IBUs from late-boil additions), so this distinction between "slower" and "less" utilization will be important to me. Commented Jun 29, 2011 at 11:29
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1@iWeasel Interesting comment about amount of acids, so where does the % utilization # come from then? Are you saying its relevant to later additions only? Good comment for thought.– brewchezCommented Jul 20, 2011 at 14:16
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@Brewchez (Double comment response here - maybe I should make it another answer) The Hop utilisation % is = (conc. of Iso-alpha acids in beer / conc. of alpha acids added to wort) x 100. It is relevant to any addition, therefore, but conditions (the vigour/length of the boil, the SG of the wort, the equipment) will all affect the final concentration of iso-alpha acids, ergo the utilisation %age. As bitterness is converted in the early stages, late additions for aroma can still have quite a marked effect on bitterness.– iWeaselCommented Jul 26, 2011 at 21:30
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I have done some further reading on this and, although a longer boil might start to close the gap, pelletised hops can have an addition of 1 - 3% magnesium oxide and/or bentonite. This increases utilisation %age because the former improves solubility and the latter the surface area for isomerisation to take place. Maybe I was a bit quick to suggest that it might be possible to simply boil for longer to achieve the same. Therefore plus one for making me think again :D– iWeaselCommented Jul 26, 2011 at 21:32