A way to test the fat content of mince/ground beef at home?
May 4, 2010 2:53 AM   Subscribe

Is there a way to test the fat content of mince/ground beef at home? i.e. (semi-)scientific procedure

I'm looking for a way to calculate the percentage of fat in my minced beef as it's important to my diet.

My supplier doesn't calculate it and says it varies from batch to batch.

Any experiments I can do at home?
posted by Not Supplied to Food & Drink (29 answers total) 1 user marked this as a favorite
 
You can probably get reasonably close.

Just cook a weighed amount of ground beef in a pan with some water. You can then drain off all the liquid, cool it to separate out the fat, and weight the fat you've obtained. You won't get a totally accurate result, because there will be other stuff mixed in with the solidified fat, and there may also be a certain amount of fat left in the meat. But at least you'll be in a position to compare different batches for fat content.

Of course, if you want a very low fat content, just choose the beef yourself and mince it at home.
posted by le morte de bea arthur at 3:43 AM on May 4, 2010


I would expect you could approximate by comparing the weight of the meat before and after cooking/draining, but you would likely need to calibrate with beef of known fat content.
posted by JMOZ at 3:45 AM on May 4, 2010


That's a good idea. I could get beef of known fat content from the supermarket. I suppose that will tell me how accurate the process is as well.
posted by Not Supplied at 3:54 AM on May 4, 2010


I think weighing the actual extracted fat rather than the cooked/uncooked beef is likely to be more accurate. Cooking beef does much more than just displacing the fat. There's likely to be a change in water content for a start.
posted by le morte de bea arthur at 3:56 AM on May 4, 2010 [1 favorite]


Another thing you could try is take a known volume (say, 100 cm³), weigh it and calculate the density. If you know the individual densities for the fat and the meat parts you can then calculate the percentages.

Drawback: you need a pretty good scale and you'll need to find out the individual densities once (maybe manually separating a test batch?).
Advantage: once you have those values you can simply weigh a known volume of each fresh batch and non-destructively find out the fat content.
posted by PontifexPrimus at 4:02 AM on May 4, 2010


I don't think it would be practical to seperate the fat and lean by hand...it's well mash up. I might find the figure for density of fat online I suppose.
posted by Not Supplied at 4:08 AM on May 4, 2010


In fact the density of fat in the mince is gonna be very similar to the density of suet which I have got. So I would just need to work out what the density of lean is.
posted by Not Supplied at 4:10 AM on May 4, 2010


So how about this:

Work out the density of steak
ditto suet

Work out density of mince of known fat percentage to see how well the calculations fare
posted by Not Supplied at 4:19 AM on May 4, 2010


le morte de bea arthur: "I think weighing the actual extracted fat rather than the cooked/uncooked beef is likely to be more accurate. Cooking beef does much more than just displacing the fat. There's likely to be a change in water content for a start."

A few comments:
First, it's going to be difficult to separate the fat from the water completely. Also, you're (presumably) measuring a smaller amount of fat, which magnifies the errors.

Second, with calibration to known standards (i.e. supermaket beef), one needs merely assume that the change in water content isn't much different for different brands of beef. That seems likely to be a safe bet.

PontifexPrimus: "Another thing you could try is take a known volume (say, 100 cm³), weigh it and calculate the density...."

I considered a density measurement as well, but the problems you're likely to face are: (1) the density difference between meat and fat is likely to be fairly small, and (2) the packing factor (i.e. the amount of air/how finely it's chopped) will impact the volume significantly unless you can somehow compress the meat very well. You could, in principle, submerge it in a fluid (e.g. water) and measure volume displaced, but then you have water-logged meat.
posted by JMOZ at 5:43 AM on May 4, 2010


Personally I think density is unlikely to be the best approach, appealing though it is to the scientific mind.

The density of steak will vary a bit depending on such things as type of muscle (which cut of beef the steak is from) and how long the steak has been aged. Mince is unlikely to be from the same cuts as a steak, and probably won't have been aged; it's also been minced, which quite quite possibly have affected the density. And as JMOZ says, waterlogged meat is going to be a problem if you do the obvious thing and displace water.

Suet, on the other hand, is made specifically from areas of harder fat (around the kidneys). And the stuff you buy pre-packaged as pellets is mixed with flour. But even if you buy a chunk of pure suet from a butcher you're not getting the same sort of fat that you'll find as part of mince. I'm not a food scientist but the likelihood of introducing significant errors there seems quite high.

Just boil the fat out of a couple of ounces of mince and weigh the fat. That'll give you a rough percentage by weight. If you can find some meat with a labelled fat content you can do the same with that and use it as a control to take a guess at how efficiently you're extracting the fat.
posted by le morte de bea arthur at 5:51 AM on May 4, 2010


My guess is that the meat you're buying is from a local butcher rather than a giant grocery store so it's likely to be a mix of whatever trim they on hand that day. If that's the case, then the fat content will vary from day to day. I'm not sure any sort of test will give you useful results unless you're planning to go through the whole testing process each time you buy meat.
posted by foodgeek at 6:55 AM on May 4, 2010


foodgeek- This is, apparently, the idea; the OP wants to know it since it varies from batch-to-batch but is important for his/her diet. This is why a simple test (such as the ones proposed by le morte de bea arthur or myself) is ideal. (For the record, I still think it's best to measure the weight of meat after cooking off the fat, while le morte... wants to measure the fat. One could, if one wants to be scientific about this, do both and compare the relative errors.)

The OP could also build or buy calorimeter, and take advantage of the difference in calorie densities of fat and protein/carbs to calculate the fat percentage. Although this is an indirect approach, I would guess the OP could actually be more interested in caloric content than fat itself. I don't, however, know the accuracy of DIY calorimeters.
posted by JMOZ at 8:13 AM on May 4, 2010


If the OP is testing each batch, the easiest thing to do will be to simmer a measured quantity in a reasonable quantity of water then dump the cooked mess into a pyrex measuring cup. The fat will float and it should be easy enough to eyeball the volume of fat to get a relatively accurate estimate. Using the same quantities with grocery store meat then marking the measuring cup will make it really easy.
posted by foodgeek at 8:37 AM on May 4, 2010


I'm not sure you could assume that you would render all of the dietary fat out of the meat. Some of it must remain mixed within the mince. If cooking rendered all the fat out of meat, there would be no real point in using higher fat mince for burgers.
posted by sagwalla at 8:44 AM on May 4, 2010


This makes me really wonder, when you buy a packet at the supermarket butcher that says 85% lean, how do they know?? Is that just estimated from what type of scraps they threw in the hopper that day, or is it measured? If you asked somebody there, that answer might help you out a lot.
posted by aimedwander at 9:51 AM on May 4, 2010


It seems that people are suggesting ways to measure the amount of fat that is drained via cooking--but wouldn't that be counter-productive to finding the amount of fat actually eaten?

Basically, that fat is already out of the meat, and wouldn't affect your diet. You need to know what's left after cooking, no?
posted by jsmith77 at 9:59 AM on May 4, 2010


I would like to know the total fat in the meat - either quantity or calorie amount. I'm not going to take fat out...I'm on a high fat diet, so looking for the %calories from fat and %calories from protein.

I'd imagine in industry they use something like this

JMOZ, could you give me an idea how a calorimeter would enable you to work out calories from fat seperately? Otherwise will try one of the heating approaches.
posted by Not Supplied at 10:54 AM on May 4, 2010


I'll elaborate on foodgeek's method, which I think is really close to a workable method, with one extra piece of equipment.

1) Scoop 1 tablespoon of ground meat
2) Boil 5-10min in 1 cup of water
3) Pour liquid through a strainer into a graduated cylinder.
4) Let settle, record amount of oil at top (ignore water level).

You can calibrate this vs. "known" 90/85/whatever % ground beef from a big store, then only use the answer to #4 as your scale -- more rendered fat than 85%, less than 85% but more than 95%, etc.

Things to tweak for better results:

a) Boiling time (short time = convenience; long time = more complete rendering)
b) Size of meat sample (larger sample = less error)
c) Try with a standard starting mass instead of standard starting volume (no time right now to think through the implications of this choice, it either helps, hurts, or does nothing...)
posted by range at 11:22 AM on May 4, 2010


Not Supplied: Fat contains 9 kcal (what is commonly called a Calorie in the US) per gram, while protein and carbs contain 4 kcal/g.

Your procedure is (in theory) simple:
1. Measure mass of piece of mince on balance (scale).
2. Measure calories of the piece of meat in calorimeter.
3. Solve (trivially easy) the following:

9*M*X+4*M*(1-X) = Total calories
where
X = percent fat
M=total mass
posted by JMOZ at 2:03 PM on May 4, 2010


Why not do exactly the same as people do to calculate their body fat percentage?

Step 1: Weigh the meat.
Step 2: Weigh the meat underwater.
Step 3: Subtract Weight #2 from Weight #1.

You're going to need a suspension scale, like these.
posted by Cobalt at 8:35 PM on May 4, 2010


Thanks JMOZ I get you. Cobalt, they seem to use standard formulas for the human body. I don't know how to work it out with beef.
posted by Not Supplied at 12:14 AM on May 5, 2010


Cobalt- people are fairly non-porous, so one needs not worry about them getting water-logged. Otherwise, that would work/could be calibrated.
posted by JMOZ at 5:47 AM on May 5, 2010


Wow, you're right. I thoight it was a lot more direct. Sorry.
posted by Cobalt at 5:59 AM on May 5, 2010


Well I could submerse a sealed packet, no? how would it be calibrated?
posted by Not Supplied at 8:31 AM on May 5, 2010


A sealed packet would have air in it. Even if you got most of the air out, you have the same packing-factor problems as you have if you try to measure the density.
posted by JMOZ at 10:29 AM on May 5, 2010


Ah ok...cause I usually get a soft vacuum pack with very little air. But if you say that's a red herring then won't go there.
posted by Not Supplied at 10:44 PM on May 5, 2010


Not Supplied: look at it this way- by comparing the weight under water, you're comparing the buoyancy in air vs. the buoyancy in water, and therefore measuring the density relative to water. The difference in density between air and meat is MUCH larger than the difference in density between meat and fat, so I would think your errors would be enormous (and quite possibly larger than the signal you're measuring) with even a very small amount of air.

If you are going to implement one of the other approaches, it would not be particularly difficult to see if this method tracks well, though, and it does have the advantage of simplicity. It's worth noting that this method is largely equivalent to measuring the volume of water displaced, which might actually be slightly more accurate.
posted by JMOZ at 9:54 AM on May 6, 2010


Thanks
posted by Not Supplied at 1:05 AM on May 7, 2010


And do let us know which method works best after you try them! Good luck.
posted by JMOZ at 5:02 AM on May 7, 2010


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