Extract guy planning a Partial Mash Kolsch

I'd like to make a Kolsch for a summer brew, and I'd also like to try and move from Extract and Grain steeping to Partial Mash. I did a search on Jamil's Kolsch, and came up with the following:

9.00 lbs Pilsner
1.00 lbs Munich Malt
.5 lbs Wheat malt

.9 oz Tettnanger Pellet at 60
.4 oz Tettnanger Pellet at 5

BrewTek CL-450 Kolsch yeast.

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I multiplied the grain bill by .75 to get appr. 6.6 pounds of Pilsner LME. I then entered into BrewTarget, and my OG was a little high. The recipe above was for 6 gallons, and I'll be doing a 5 gallon partial mash - so I scaled the Pilsner LME down to 6 pounds.

My plan is:
6.0 lbs Briess Pilsner Extra Light
1.0 lbs Munich Malt
.5 lbs Wheat malt

Do a partial mash on the Munich Malt and the Wheat Malt for 45 minutes (at 154 degrees?). Sparge. Bring to a boil. Take the pot off the stove and add the LME (yep, I've boiled over on the glass top stove too many times, and scrubbed too much to want to do that again!). Add 1 ounce of Tettnanger pellets at 60 minutes. Add 1 ounce at 20 minutes. Add .5 ounces at 5 minutes.

Using BrewTarget, if I do a partial mash at 5.5 gallons (with a target boil of 6.34 gallons), the numbers come out right. However, I don't have a pot that big, and my stove is not going to boil that much water. If I do a partial mash and partial boil, then add water at the end to bring it to 5 gallons - do I need to increase my hops?

Adding 1 ounce hops at 60 minutes, 20 minutes and 5 minutes bring the IBU to where it should be (but on the low side). But would that make it not to style? Should I use more hops early in the boil, and less later?

Finally, if I wimp out and decide to just go with LME and steep grains - would I substitute in CaraMunich and CaraWheat at the same weights? Or would that be too sweet, and I'd need to look for other alternatives? (I'm strongly considering trying Partial Mash - so the question is probably just academic).

Looks good to me, I don't know if the CaraMunich/CaraWheat will make a big difference or not, I haven't used them much, but I assume the difference would be small.

The idea of using Munich is fine because you are using Briess pilsner malt. It'll bring it back a little bit closer to German malt.

I would greatly reduce the mash temp down to 148-150F to get a lighter body. This is a summer beer after all. Also, adjust your grains (if necessary) for around 4.5 to 5.0%.

M_C

Definitely go for the partial mash if that's the way you are leaning. I use Deathbrewer's easy stove top partial mash pictorial. Head down to Home Depot, pick up a $5 paint strainer bag and you're ready to go. Depending on the pot size you've got, you could even mash a little pilsner malt with the munich and wheat. My 3 gal boil pot can hold 5-6lb of grain, and it might help to keep the color down (sometimes lme can be darker than expected, even pilsner).

As for the hopping, I don't see anything wrong with 60, 20, and 5 min. additions if that's what you want to do. Might have a little more flavor than Jamil's version, but I don't know if I've ever brewed a recipe without tweaking it a little. If you do a partial boil and top off with water, it can throw your hops off, depending on how much you are planning to boil. But you can avoid all that hassle (and some of the darkening effects of the lme) by adding some of your extract as a late addition. I generally boil around 2.5gal for a 5gal batch, so I try to add half my extract at the end. Do a quick search for late extract additions and it should help explain it if I haven't done it justice!

Edit: When I say I add half my extract, that would be for an all-extract brew. When I'm partial mashing, I generally try to get half my fermentables from the mash and the other half from extract, so I add all the extract late (half the fermentables).