I will give you here some information about beer in the city and also some local tips ;-)
LA ZARAGOZANA
If you can plan your visit to Zaragoza with time you can try to book a visit to the city brewery. It is not a beer museum nor a tourist's attraction and it is not open to the public. It is the actual factory so it is only open to groups for one tour in the morning or in the afternoon during the week (I think it is only in Spanish but you should verify that). You might be lucky and be able to join a group visit. I found it really interesting, they still use machinery of more than 100 years old that works perfectly today. Give it a try. AMBAR
Anyway, you do not need to complicate yourself to try all the beers from this brewery. In Plaza de España you will find the "Gran Café Zaragozano" just in the corner at the entrance of Puerta Cinegia. It is a brown café decorated with La Zaragozana and AMBAR beer paraphernalia.
La Zaragozana makes AMBAR beer for the city since 1900. Some years ago they started brewing the AMBAR 1900 with their first recipy. It is very good, as the AMBAR ESPECIAL, in fact they taste very similar which means that the recipy has not changed much.
There are several types of AMBAR, Especial, 1900, Export (with 3 malts), Caesaraugusta (made of wheat and named with the Roman name of the city), Sputnik (with vodka), Negra (stout), Lemon, 0.0 (without alcohol), Mansana (lemon and apple without alcohol and no added sugar)...
You will find AMBAR in every pub and café in Zaragoza and the whole region of Aragón. Their capacity does not allow them to export to the rest of Spain but there is an AMBAR you can find in the supermarkets everywhere in Spain. It is the free gluten AMBAR ESPECIAL for coeliacs and I can tell you it tastes the same that the AMBAR ESPECIAL, it is very good indeed. There is even a non alcoholic version, AMBAR Green without gluten.
Craft Beer Pubs
In Zaragoza as in the many other Spanish cities there are new breweries, craft beer pubs and shops. The beer panorama is becoming really interesting.
My dream is coming true! The wine country is learning and experimenting with barley (we have a lot in the region) and hops (we also have wild hop not far from Zaragoza) creating delicious beers.
Tabierna Ordio Minero
Espoz y Mina 7
This was the first craft beer pub opened in the city center a couple of years ago to promote the craft beer Ordio Minero from Blesa (Teruel).
Ordio Minero is a delicious black beer. Teruel (Aragonese province below Zaragoza) has coal mines and the villages in the area are known by their mines but as in the rest of Europe many of these mines have already closed. Ordio is the Aragonese word for barley and by extension also for beer. I really like this beer but they do not always have it on draft as the same browery produces more types now and they also have international guest beers.
The draft beers selection changes very often, just pass by and choose something from the blackboard.
In this pub you could order a beer in Aragonese "meteme un ordio" or "meteme una biera". Of course with this selection you would have to be more specific and choose one from the blackboard or the fridge.
You will also find two or three beer tapas to choose to accompany your ordio.
Beer Corner
Heroísmo 2
Craft Beer Pub with rock and heavy music. I like the the interior and the music. They have a lot of interesting beers, have a look to the blackboard and the fridge. You can also find here some food to accompany your beer.
Prices are ok and staff is friendly. The only thing I did not like here is that the service at closure is a bit chaotic. I felt the management was chaotic, maybe because they had not been opened for long yet and they were still starting.
Hoppy
Casto Mendez Nunez, 36
This is the most expensive one. Still go in and give it a try. As the name indicates most of the beers they have are hoppy (they have more hop, or aromatic hops). If you are into bitter beer you will for sure discover some new good beer.
They also have beer food. They make elaborated bier tapas, very nice stuff but also a bit pricy.
If you are looking for a nice place to chill and enjoy some beers with beer tapas it is a good option.
What to visit
You must visit "la Aljaferia". It is a castle and the guided visit is worthy and cheap. You have an overview since the first castle built there up to nowadays where the regional parliament sits.
What everyone goes to see is the Basilica "El Pilar". It is huge and in the middle of the city next to the river. You cannot miss it. Once you are there I can tell you that the Cathedral "La Seo" just at one of the side of the plaza del Pilar I find it nicer. This one is paying but the entrance is cheap.
Also in the area you can see "El puente de piedra" with the lions. It is one of the oldest bridges over the river.
You might pass by "La puerta del Carmen". It is one of the old doors of the city walls, symbol of the resistance against the French. It is not to visit or pass below just to see if you pass by.
Have a look to the Roman rests. you can visit the Foro, Theater, Roman baths... they are also in the center of course.
If you are staying in the center you can visit almost everything on foot. See the map.
The tourist office is next to the old city walls so you will pass by on your way to Plaza del Pilar. Just drop in and they will give you the exact location of the Roman rests and timetables, maps of the city...ask how to get to the Aljaferia.
La Aljaferia is the only thing that is not in the city center but it is not far and it is really worthy. Please visit it as well, it is really worthy.
Tapas
Since less than a year you can go to the first floor of Puerta Cinegia (Plaza España) and find all type of tapas and raciones (portions), wines and beer. Here you can find really everything, from the traditional "papas bravas", to a tapa with foie or a chuletón de buey. Also seafood, nice desserts, really everything from the most representative restaurants of the city in one place. The waiters will take your order and bring your AMBAR (beer of the city from the Zaragozana brewery) to your table. For food you have to have a look and go to order yourself. The tables are common and each one can order something different to eat from a different stand, no problem.
For the authentic and traditional tapas expereince, go to "El Tubo". They are the old small streets between la plaza del Pilar and Plaza de España. The smaller and oldest the bar is, the best :-)
My favourite is the oldest one. It has not changed since it opened and it is run by a very old couple. It is the "TEXAS" in a corner on el tubo.
If you get to el tubo crossing from Plaza España through Puerta Cinegia (comercial passage) you see it directly. They are old and open when they want. Anyway, I must warn that many people find it filthy and don't dare to go in. I don't think it is filthy but authentic and not renewed. The speciality is papas bravas but I prefer other things like calamares, puntillitas (small fried calamar), morro (pork scratchings)... that kind of very authentic stuff.
If you want to go for something authentic but more adapted to the times "La Migueria" is very good. Migas is a dish made with bread crumbs.
Bodegas Almau is a must in the area, huge variety of wines and the speciality is "salmuera con cazalla" (brine anchovies with a bit of very strong liquor). You can order the normal ones. And if you feel like trying something new they won a tapas contest with the "Dulce de anchoa". It is a piece of bread with spread cheese, anchovy on top and chocolate shavings.
Los Vitorinos is one of my favorites. Start with the "tapa de la casa" and have a look to the bar to choose your next one. It is expensive for Spanish standards but very good quality price relation. It is very small and you have a tapa and drink standing at the bar.
"La Republicana", el "Donde Siempre" also in the area are as well very good.
Then, if you are staying is some other area apart the center, in every area there are good tapas places but you need to ask or check in the internet.
In "La ALmozara" one of the areas I found my new favorite "El Cervino" in calle Ainzón 18, Zaragoza, España
In "Las Delicias", around plaza Roma, have an aperitivo in "El Berlanga" in Calle Escosura at the corner with calle Martin Cortés, my favorite's gambas en gabardina. Not far, in calle Bretón "El Emir" and in calle Franco y Lopez the mithical "Montesol" just in front of the city (university area).
Don't be scared to go in and try new places. :-)
Have fun!
Cheers!