Magnum hops in a Kolsch?

[Btaz]

I'm copying the (Black Widow Kolsch recipe, but have made some adjustments for my efficiencies and losses which puts my hops Hallertauer hops to 1.25oz (60min boil). Since the hops come in 1oz bags I'm thinking about just using 1oz of Hallertauer and then using 0.25oz of Magnum which is leftover from my last batch. Seems to look like the profile is about where I want it (brewtoad recipe), but I'm wondering if anyone has any thoughts on the taste/smell impact as I'll know is what I've read from freshhops

Magnum

A German thoroughbred with limited Pacific Northwest plantings. Prized for its high bittering value, the aromatic nature is one of spice and citrus.

Hallertauer

Named for its origins in the Hallertauer region of Germany, this is a noble aroma hop with ever-so-subtle flower and spice fragrances defining its “über alles” superiority. Very low bittering value.

 

[JohnK93]

I don't think the Magnum would have any major impact on the taste/smell of the Kolsch and would be appropriate for the style. But if I understand you right, you want to substitute .25oz of magnum for .25oz of hallertauer, which won't give you the desired IBU because Magnum has a lot more alpha acids than Hallertauer (about 15% versus 4%). You're going to have to do some math or use an IBU calculator to figure out how much Magnum would replace .25oz of hallertauer, but it's going to be a small amount (about 2g?).

Hope this helps,
John

 

[MedicMang]

What is the hopping schedule? If there is a bittering AND an aroma time, use the magnum to bitter to the proper ibu and then add the hallertauer as the aroma. Johnk is right about the AA% needing looked at for adjustment.

 

[Btaz]

Thanks. I'm going to add both for 60 min boil. The magnum push up the ibu compared to the recipe that I'm based off of which was 23 ibus, but I still land within the range (20-30) for a Kolsch at 26

 

[MedicMang]

Well cool man. I'm sure it will taste deeeeelish.