Because they use modernist ingredients, these amounts are given in metric by weight. For more information on how to measure modernist ingredients check out this article.
225g shrimp, either small shrimp or cut into bite-sized pieces
Preheat a sous vide bath to 132°F (55.6°C).
Salt and pepper the shrimp, seal in a sous vide pouch, and cook for 20 to 30 minutes. Remove from the bath and set aside until after the cheese sauce is made.
Preheat an oven to 450°F (232°C).
Place the dried peppers in a bowl and add enough water to cover. Let sit for 30 minutes, or until soft. Remove from the water, cut off the stem, and remove the seeds.
Coat the onion, poblano pepper, garlic, and tomatoes with oil then salt and pepper them. Place on a roasting sheet and cook until just starting to blacken, about 15 to 25 minutes. Remove from the heat and let rest until cool enough to handle.
Dice the roasted vegetables and rehydrated chile peppers and set aside until the cheese sauce is done.
Add the beer and milk to the pot and whisk in the sodium citrate. Bring to a simmer then slowly add in the cheese while pureeing with an immersion blender.
Once all the cheese is incorporated and the queso is smooth, stir in the shrimp and diced vegetables. Serve with chips or bread for dipping, or use as a sauce.