How to keep Guacomole from turning brown??
I need to pre-make a substantial amount of Guacomole for a party but don't want it to turn ugly brown before I serve it. I would like to make it in the morning and then serve it in the late evening. Any suggestions on what to do? Does just sprinkling with lime before putting in fridge work? Or can I make it and freeze it and then thaw as needed? Or has anyone tried that powder Fresh Fruit? Thanks in advance.
In my experience, guacamole is best made shortly before serving if at all possible, because the longer it sits, the browner it will get. Lemon or lime juice over the top will help keep it from turning for a while but is not a cure all. Putting the pit in does *not* help in my experience, as whatever portion of the guacamole is touching air or surface of any kind is subject to browning (i.e. the portion next to the container wall will brown a bit the longer it sits). The only solution I've found is to scrape off or avoid the browned parts when serving.
I've never tried freezing fresh guacamole so don't know if that is an option.
re: Chino Wayne
Harold McGee agrees with you about using Saran Wrap. He has tested many of the plastic wraps and found that Saran Wrap is the most air tight - that's why it doesn't cling as well as some others. (Ever wonder why a wrapped onion still makes your fridge smell?...)
All the others will let some air in (albeit slowly) and since the OP wants to keep the guac for many hours, it may make a difference.
As you said, press the wrap directly onto the surface .... HMcGee also tested the avacado pit and found out that a light bulb worked just as well when substituted for the pit.....mmmmm.
The browning is a chemical oxidation that results from contact with the oxygen in air. Citrus juice contains ascorbic acid (vitamin C), an antioxidant, that will help to prevent browning, which is why sprinkling lemon or lime juice over the surface will help. If you do that and also press a covering of plastic wrap down into the bowl so that it's in contact with the guacamole (i.e., not stretched across the top of the bowl), then refrigerate, you should be able to keep things green for a reasonably long time. You may need to dispose of the small amount of guacamole that will remain attached to the plastic when you remove it.
Don't freeze it once it's put together. The water will draw out of the vegetables and you'll have a soupy mess after it's thawed.
I actually do think that putting the pits back in helps a little, but the most important thing is to keep oxygen out. So be sure to put plastic wrap right on top of the guacamole, and work the air bubbles away with your hands (same idea as keeping a skin from forming on a pudding).
All the posters got it right with the plastic wrap directly on the surface. Just one additional hint...since only the surface turns brown (not the entire container), you can stir in any brown surface to disburse it. The top 1/16 inch of brown mixed into 4" of green should result in a green mixture.
or you can perform 'quality control' on that top 1/16"