Never let the oil get past 350 or 360 and burning should not be a problem. The oil will be full of seasoning residue from the previous turkeys and may have some effect on the taste. I wouldn't let that slow me down considering the ridiculous price of peanut oil.
As long as you don't burn your oil 5 birds should be fine. If the oil starts looking like it has too much seasoning floating around, peel a couple big taters and toss em in for a minute. They'll pick up the seasoning and clean up the oil.
we've done 4-5 with same oil before... just keep temp correct as noted, add oil when necessary.. I assume turkeys are all same size for your pre-measurement so you do not get overflow when putting in the birds?
I am no expert but we fry about 15 birds a yr between Thanksgiving and Christmas.....I have a 60 qt pot that requires 9 gallons...thats $120 last yr.....and I bought one of the filter pumps for the grease a couple of yrs ago......I will be using the same grease as last yr and it fryed about 20 birds.....The best marinade that I found to not leave residue in the grease is Cajun Maranade Creole Butter......I will take a hard look at the grease after Christmas and see if it is still good to go one more yr....at the price we pay for this stuff I want to get all I can out of it without screwing up the birds......When you get finished cooking in the grease there is nothing left in it to spoil the grease(due to the temp) so it your choice whether you chunk it or not .....I have been doing this for about 12 yrs and have never had any bad birds due to grease or any thing else......
One trick I will chunk out there for 2coolers......the old recipe called for 10-12 lb birds at 3 minutes per pound which is about 30 minute cooking time in 350 degree grease......we have found out that you can cook a 14-15 pound bird in the same heat for the same amount of time......"TRICK" when you take a bird and cook him 3 minutes per pound and he weighs 15 pounds ....you will dry him out and you might as well cook him in the oven.........take a large bird and cook him exactly 30 minutes
Pull him out of the grease and immediatly wrap him in foil and put in an icechest.....he will continue to cook for a while......you need to check the internal temp with a meat thermometer and make sure the internal temp is above 160 degrees.......if you have acheived that temp with him sitting in an icechest you have fully cooked the bird and he will not be dry.................
Remember safety this yr while cooking with hot grease.......
1. check your grease level with water and your turkey before heating grease.....put bird pot and fill with water.......always keep grease level about 3-4" below top
2. never put pot, burner, and propane bottle in a high traffic area
3. keep kids away from pot
4. make sure your bird is thawed out
5. never cook on wooden deck(dont ask me how I know this)
6. keep propane bottle and pot close(so there is no line for somone to trip on)
7. never overfill with grease
8. make sure you have good potholders when lifting lid, bird, or anything else that is hot
9. I would avoid alcohol and grease....as they do not mix well
10........Enjoy your thanksgiving everyone and May God Bless Each and Everyone of you and our Troops as well
tHAT NOT NESSESARY IF USING PEANUT OR COTTONSEED OIL. hIGH FLASHPOINT AND WILL NOT CATCH FIRE IF OVERFLOW...
bE SURE TO MEASURE HOW MUCH OIL YOU NEED 1ST. iF NOT SURE, DROW BIRD IN POT WITH WATER TO GET LEVEL MARK 1ST.