Guinness Nitro Cold Brew Coffee by Guinness St. James's Gate Brewery is a nitro coffee stout with a traditional dry Irish stout as the base beer. Generally, with the addition of coffee (which is classified as a spice in culinary world) that moves the beer from 15B Irish stout to Category 30A. 

The aroma is full of milk chocolate, very similar to chocolate milk. There is a very low coffee note, but it’s not very assertive. The overall roast profile of the beer seems a bit low for a coffee stout. Chocolate seems to be the dominant aroma here. Hop aroma is void. Visually, it’s a very good-looking beer. It’s a
nitro beer so there are no visible bubbles in the beer once everything settles. The beer is black with a very tight and dense foam on top of the beer. The head is light tan and very long-lasting. Retention is very high. Moving into the flavor, we have a very light roasty and mild grainy flavor. The base beer is dry
and a little bit lacking in overall roasty flavors. Hoping for a little bit more as it comes across watery. Hop bitterness is moderate with no hop flavor. The coffee flavor is also on the low side, so they were very restrained with the coffee additions here. Roasted grain would be the dominant flavor overall.

The beer is light-bodied and close to watery. Due to the nitro effect there is a very creamy texture to the beer, and it's not effervescent at all, which is expected. There is no alcohol warmth or flavor. Grain astringency is non-existent.

Overall for a coffee stout it’s very thin and not all that assertive, even for a standard Irish stout. The milk chocolate flavor was a bit odd compared to what I was expecting for a beer billed as a coffee stout. The actual coffee was pretty low and if it wasn’t listed as a coffee stout, I would have thought it was mostly
an attribute of the grain bill. All in all, an average beer as a spice/herb/veg but the base beer seems very good. Not bad at all but nothing to rush out and buy in my opinion.