Hop Bitterness Dilution Ratio

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Hi All,

Gonna give no-chill a crack next brew.. i've got a heap of 15L cubes, so my plan was to make a bigger/bitterer beer to 15L, then dilute with 5L of water when i throw her in the fermenter.

Now if i build a recipe in BeerSmith to 20L, to my final desired bitterness & OG - and then just use those ingredient amounts in making 15L of wort and then dilute - will i end up with 20L of wort to the original recipe? or is there a ratio/conversion calculation to figure this out?

Cheers all
No, there no need to adjust bitterness in those circumstances IMO, it is all fairly linear and just make your hops additions as though it has the final diluted volume. However if your boil gets into higher territory, theoretically you can adjust to compensate for poorer bitterness utilisation/ extraction efficiency. I haven't found it necessary to do so myself, however most of my (MaxiBIAB*) beers are <6% ABV and <50 IBU so less likely to suffer anyway. A rough utilisation efficiency compensation formula is for every 0.010 above 1.050, add 10% to the IBU target- nb. this is more about bittering and less about any impact on late kettle additions. Importantly, when adjusting, you need to consider the average boil SG (not a simple thing to do- another reason why I don't really bother!) and not the diluted OG.
Hope this helps! :icon_cheers:
* MaxiBIAB uses a concentrated boil and fermenter dilution with kettle SG of around 1.070 and above.
Great stuff. Thanks.

As long as it doesn't throw me right out, i'm happy with that for now. If i do a bigger beer ill do throw a little extra in just to be safe, cant go wrong with more hops in a bigger beer anyway =)

Cheers =)

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