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Crab with Ammonia Odor Question???

i bought some live crabs the other day. the method of cooking was steaming.

after they were finished upon smelling the meat it had a strong odor of ammonia. what is this? what does that mean? were they not fresh?

they didn't taste bad....but the smell was off?

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  1. Hi Larry. My husband ordered cioppino with crab several years ago while on a trip to San Francisco and he was alarmed to find that his soup smelled of PineSol. We have always wondered why.

    1. larry,

      I have run into this as well. Since I live in Illinois mostly frozen crab is available here. I can get live Dungeness, but have to travel to get it. I have noticed that "amonia" smell as well when steaming snow crab in the past. Mostly the body segments. I have no clue what it is, I always thought the crab may be old. Either way it goes in the garbage.

      1. If you smell ammonia, it's too late. Toss them (or return them immediately to your fish monger, where you should expect and receive a refund).

        3 Replies
        1. re: Covert Ops

          Exactly.

          If you smell that in a restaurant, send it back, leave, and never eat there again.

          1. re: Robert Lauriston

            Had halibut like that at a defunct restaurant just off Third Street Promenade in Santa Monica. It was heinous. Sent it back, refused to order anything else, just ate the sides, paid and left, vowing never to return. It had been an excruciating wait for the food anyway, although my husband said his steak was good.

            That restaurant deserved NO second chances. At the time, it was packed.

          2. re: Covert Ops

            Hi! My parents bought crab yesterday from a korean grocery store. They didn't have that ammonia smell just until we were about to eat. My mom cracked up a crab and had noticed the smell of ammonia. To our disgust, we stopped eating them and put them aside to take back to the store the same day we got them..(I looked it up on the internet and found this page) Then my mom called up the store had spoken to the manager. The manager asked if we can just come back the next day (how stupid). My mom was like listen your crabs smell like ammonia and we couldn't eat them so we are taking them back for a refund ( we had the proof). So when my mom had finally arrived at the store, she spoke to the manager and he said that he couldn't give us a refund because they had been cooked. He said that when we got them they were FRESH (what a dumb---) He wanted us to return the bad crabs alive so they could sell it to others (what a crook) There's something wrong with that store.. First off we got overcharged. The cashiers just punch random numbers so if you don't check your receipt you're defeated ( It happened to my mom's friend who goes to shop there (what a coincidence). Second, they sell expired stuff and it happened to our friend who goes there to shop as well (another coincidence). And now the crabs..I'm still heartbroken (I feel sorry for my parents that it happened to them)..It's not right..

          3. So odd! A few years ago I dined at a restaurant. I had skate wing, and it smelled strongly of cleaning solution. I was really grossed out, especially because I still ate most of it. What does it mean???

            2 Replies
            1. re: cherie

              Ammonia is what fish & shellfish excrete...they don't produce urea/urine like mammals. So if you're smelling ammonia, the fish or shellfish is WAY WAY past its prime. Fresh seafood has NO ammonia smell. That smell is a product of decay.

              1. re: cherie

                Skate and rays and shark are not fish, and they have to be skinned and ripened properly (for 24 hours) to avoid an ammonia taste. For those creatures, it does not mean it's old so much as it was not handled and prepped properly

              2. My understanding is that the ammonia smell is a result of deterioration of the seafood. I got hold of some bad crab once and some bad shrimp. It smelled like someone had opened a bottle of Parsons in the kitchen. Phew.

                3 Replies
                1. re: Andiereid

                  Yes, ammonia smell is prime indicator of deterioration, but that doesn't really answer the question as to why live crabs would exhibit that odor after being steamed. By definition live crab would be fresh crab...

                  1. re: djohnson22

                    I was thinking the same thing. Ammonia would only be present in dead crabs past their prime.

                    To the OP, were all the crabs alive before you cooked them?

                    1. re: djohnson22

                      LIve crabs are often kept in a tank for a long time, perhaps too long. They are still, however, excreting into the water of the tank. If the water in the tank is not cleaned frequently enough, the crabs filter and absorb enough of their fellow crabs excreted waste to smell, and/or taste funky. This means that the place doesn't keep their tanks clean enough, even tho the crabs are alive.

                  2. The same thing happened to me 6 years ago and I've never forgotten it that awful smell. It was in a Chinese restaurant in Hong Kong and the preparation was something like a crab/shrimp meatball, very dense. Well, the seasoning and deepfrying didn't mask that potent smell of ammonia. I remember asking the manager to smell the crab-balls and he claimed not to notice anything.

                    Thanks for posting this! I thought I was nuts...

                    1 Reply
                    1. re: frenetica

                      I've had a similar experience... was having dim sum with friends, and someone claimed to smell bleach in the har gao. I tried sniffing and sniffing but could not detect it. Dunno if it was actually an employee walking by with cleaning solutions.

                    2. I was wondering if maybe "parts" of those crabs weren't so much alive anymore? If they were old and tired and barely alive, maybe? Probably a screamin' reach, but it crossed my mind. Crabs with gangrene?

                      1. Toss 'em. I hate that smell, I once bought some skate wing which had this smell and I haven't been able to ever buy it or eat it again.

                        1. Wow. I just picked up an Alaskan King Crab leg from the grocery store yesterday. The fishmonger always does us right and she said that the crab, even though frozen, were probably past their prime, so she gave us a free one to try out. After cooking and shelling, the meat had a very strong ammonia odor. I called her up and she said throw it out and she'll give us another free one when the next shipment comes in :) I can't recommend enough that you have a good relationship with your fishmonger. :)

                          1. I agree the ammonia might mean going bad or gone bad. But at one time I caught my own dungeoness crabs, I took some home and cooked them, live. They both smelled of ammonia when I cracked them open. And they were fresh. I did some research and concluded that the region I caught them had ammonium nitrate in the water from pulp mills on the same water way. I think the heat of cooking caused the chemical reaction and release of ammonia. I may be crazy but it was all I could conclude. I also had some store bought crab that was ammonia smelling, and no matter how hungry or strong your stomach is there is no way anyone would eat it. throw it and tell your fish supplier that it was bad bad bad...

                            1. This site gives reasons that caused ammonia smell: http://www.ari1.com/id41.htm

                              In case it goes away, here is the detail:

                              WHERE THE AMMONIA COMES FROM

                              DECOMPOSING MORTALITIES
                              THE METABOLIC PROCESS (OFF THE GILLS
                              )SILT/MUD
                              FECES (POOP)
                              REGURGITATED FOOD

                              At times it might seem that there is a conspiracy of ammonia producing sources intent on killing your product down to the last crab. However, once the potential sources are identified the conspiracy seems less threatening. The main sources are, in order of potential severity of concentration:

                              1) DECOMPOSING MORTALITIES :
                              The main thing to remember here is that from virtually the moment a crab dies it starts to decompose and just gets worse from then on. How fast things go to hell depends mainly on the temperature of the water . The colder the water the slower the decomposition. I don't have any hard science to back this up but a rule of thumb I use is that one 2 lb. mortality left in a system for 24 Hrs.can equal the metabolic ammonia output of 50 Lbs.of live crab.
                              ACTION TO TAKE: PICK THROUGH AND REMOVE DEAD OR WEAK CRAB AT LEAST ONCE A DAY.

                              2) THE METABOLIC PROCESS (OFF THE GILLS):
                              In a clean, well maintained system this is the main source of ammonia and is easily handled by an adequate bio-filtration system. As the crab respires ammonia is released from the gills as a natural part of the metabolic process. The higher the temperature, the higher the metabolic rate, the more ammonia is produced per pound of product.
                              ACTION TO TAKE: REDUCE THE SYSTEM TEMPERATURE TO 38 DEGREES F. FOR BULK HOLDING AND 40 DEGREES F AND UP TO 50 DEGREES F. FOR DISPLAY TANKS. KEEP A WELL MAINTAINED BIO FILTER OF SUFFICIENT CAPACITY RELATIVE TO THE POUNDS YOU ARE TRYING TO HOLD. WATCH YOUR DISOLVED OXYGEN.

                              3) SILT/MUD:
                              Most first receivers know about what I call 'storm crab'(those crab that have been in the pots through a storm and, as a result, are extremely dirty and, depending on the length and severity of the storm, possibly weak). Storm crab are at the extreme end of the spectrum of the dirty crab syndrome. Much of the silt or mud brought in with the crab is of an organic nature rather than of a silicon nature like sand would be. It decomposes so rapidly that when I tried to have it analyzed one time the lab trying to measure the particles microscopically gave up because it was dissolving as they measured. A certain part of the stuff is, however, stable enough to collect in your bio-filter causing clogging, channeling and therefore reducing the effectiveness of the bio-bed resulting in increased ammonia due to ineffectual bio-filtration.
                              ACTION TO TAKE: FIRST RECEIVERS: TRY TO SEASON THE CRAB AND SORT ONCE BEFORE SHIPPING. SUBSEQUENT RECEIVERS:RINSE THE INCOMING PRODUCT BEFORE PUTTING IN YOUR TANK EVEN IF YOU HAVE TO USE FRESH WATER FROM A GARDEN HOSE. DO NOT SUBMERGE THE CRAB IN FRESH WATER.
                              4) FECES (POOP):
                              Not many options here is there? The good news is that for other than first receivers there's not much left by the time you get them. It's not a significant source of ammonia anyway.
                              ACTION TO TAKE: FEED 'EM CHEESE (just kidding)
                              5) REGURGITATED FOOD:
                              Unless you are a first-receiver you probably don't have to worry about this unless it is very early in the season and your supplier is "short stopping" your crab ( just giving them a drink before shipping to you) or direct shipping from the boat. First receivers may have to deal with a fairly significant amount of bait, especially squid, when the gear is getting turned quickly at the beginning of the season.
                              ACTION TO TAKE: WHEN YOU NOTICE SOMETHING NASTY HANGING OUT OF A CRABS MOUTH OR FLOATING AROUND IN THE WATER, GET RID OF IT.

                              1 Reply
                              1. re: 1monalisa

                                Probably too much information there.....but thanks for the warnings. Maybe you should change that screen name to "Ammonialisa"? '-)

                              2. Who would eat something that smells like ammonia? I don't care what's causing it, out it goes.

                                1 Reply
                                1. re: pikawicca

                                  Or at the very least, make a lavender, mint or pine beurre blanc to go with the smell!

                                2. OMG! Jut last week I got some wild cod at Costco and fried some for fish tacos. It smelled funny, sweet, yet ammonia like...I just couldn't figure it out, never smelledfish like this before. My daughter and husband said it was ok, but I could swear it was ammonia smell! Now I know...

                                  1. I hadn't had hardshells in a few years and had a craving today, so I bought 2 cooked blue crabs at the market and brought them home for lunch. I just ate them cold. The first one had a slight ammonia smell, and didn't taste right but also didn't taste bad, so I kept eating it. I sort of had an uneasy feeling, but thought it must just be the seasoning etc. But then, I started on the second one, and it was beautiful and delicious and just how I remember. I sucked clean every bit of shell there was. So clearly the first one wasn't very fresh, but should I be worried?

                                    1. I live in the Bay area so I catch my own crabs. This past weekend, we caught more than a dozen crabs and decided to boil, steam, and fry them. The boiled ones reeked of ammonia, the steamed ones did not smell much and the fried ones smelled the least of all three methods. The big mistake was holding them in a container with non moving water, which explains the ammonia buildup. However, I do not understand why the steamed and fried ones did not have this smell. My theory is that the steaming and frying processes somehow made the ammonium evaporate. The frying method completely got rid of the ammonium smell.

                                      1 Reply
                                      1. re: ln_gao

                                        I only keep freshly caught Texas blue crabs in water for a few minutes. The crabs will use up the oxygen in the water and asphxyate. The fresh crabs I catch are put into an ice chest and covered with a wet towel, but only briefly. They will keep a long time without water, but too much will kill them. This is my experience with blue crabs, I assume you live on the west coast and are talking about a different crab.

                                      2. Ammonia is one of the components that proteins break down into. In marine as well as freshwater organisms, it can be from their excretion of waste or their actual body parts breaking down.