Generally, halving the recipe is just the amounts (except for yeast). To make sure, though, you may want to post the recipe here and we can take a look and see if it should just be halved.
Here's the recipe courtesy of Blacklab in the American ale section
Recipe Type: All Grain
Yeast: Safale-04
Yeast Starter: no way
Additional Yeast or Yeast Starter: nyet
Batch Size (Gallons): 5.5
Original Gravity: 1.054
Final Gravity: 1.013
IBU: 34
Boiling Time (Minutes): 60
Color: 9.0L
Primary Fermentation (# of Days & Temp): 10 @ 60-ish
Additional Fermentation: n/a
Secondary Fermentation (# of Days & Temp): 14 @ 60-ish
Tasting Notes: Orange/coriander low in the profile, compliment fruitiness from Cascades.
Cascades Orange/Coriander Pale Ale
10-A American Pale Ale
Size: 5.5 gal
Efficiency: 68.0%
Attenuation: 75.0%
Calories: 178.22 per 12.0 fl oz
Original Gravity: 1.054 (1.045 - 1.060)
|=================#==============|
Terminal Gravity: 1.013 (1.010 - 1.015)
|==================#=============|
Color: 6.0 (5.0 - 14.0)
|===============#================|
Alcohol: 5.27% (4.5% - 6.0%)
|================#===============|
Bitterness: 33.78 (30.0 - 45.0)
|============#===================|
Ingredients:
9 lbs Maris Otter
1 lbs Vienna Malt
1 lbs Crystal Malt 10°L
1 oz Cascade (5.5%) - added first wort, boiled 60 min
1 oz Cascade (5.5%) - added during boil, boiled 10 min
1 oz Cascade (5.5%) - added during boil, boiled 5 min
1 oz Cascade (5.5%) - added during boil, boiled 1 min
2 ea Fermentis S-04 Safale S-04
2.0 oz Cascade (5.5%) - added dry to secondary fermenter
2.0 oz Orange zest - added during boil, boiled 10.0 min
1 oz Coriander crushed - added during boil, boiled 10 min
Whirlfloc - added during boil, boiled 15 min
Times and temps stay the same. The ingredients won't release their yumminess any sooner if they are fewer. Something about science...
cheers
I kind of figured but didn't want to screw it up. Thanks