Adding Lactose to a Golden Stout Extract Recipe Kit

[beer-me-now]

I'm new so please forgive me if this is completely obvious.

1 Gallon Golden Stout Recipe Kit from Craft A Brew:

3.75oz American Smoked Malt & Flaked Oat Blend - Specialty Grains
1.25lb Pilsen - DME
0.35oz Willamette Hops
0.20oz Goldings Hops
1.00oz Coffee Beans
1.00oz Cacao Nibs

My intention is to add 4oz lactose to the above (going for a Noble Ale - Naughty Sauce type of feel).

Do I have to reduce the weight of some of the ingredients above, 4oz less of the DME for example, or can I just add the lactose and keep all the ingredients exactly as listed?

If anyone can further enlighten me as to the "why" I would or would not need to make adjustments I would also be very grateful for the knowledge.

 

[tri_clamp_ninja]

If you are looking to simply add sweetness and body then keep the grain and dme bill the same. You will see a high of and higher fg as a result but should have similar attenuation and alcohol content. Only reduce the DME of you are looking to reduce the alcohol content.

Lactose works by adding long chain sugars/proteins that are not consumed by your typical beer yeast therefore you see the higher gravity readings due to higher sugar density however your yeast will still consume what it can from your DME, grains, etc so your final alcohol content will be about the same. Keep in mind wine and champagne yeasts, wild yeasts (Brett, lacto, pedio), and beer spoiling bacteria can convert those sugars so if your sanitation is not spot on you face higher possibility of infection related refermentation occurring with lactose treated beers.

 

[beer-me-now]

If you are looking to simply add sweetness and body then keep the grain and dme bill the same. You will see a high of and higher fg as a result but should have similar attenuation and alcohol content. Only reduce the DME of you are looking to reduce the alcohol content.

Lactose works by adding long chain sugars/proteins that are not consumed by your typical beer yeast therefore you see the higher gravity readings due to higher sugar density however your yeast will still consume what it can from your DME, grains, etc so your final alcohol content will be about the same. Keep in mind wine and champagne yeasts, wild yeasts (Brett, lacto, pedio), and beer spoiling bacteria can convert those sugars so if your sanitation is not spot on you face higher possibility of infection related refermentation occurring with lactose treated beers.

Thank you for the detailed response - much appreciated!