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Calorie value of spent coffee grounds per gram?
Hi everyone. I'm interested in trying my hand at integrating spent coffee grounds into recipes for making various foods as an experiment, but I am also in the process of controlling / reducing my weight and log my calorie intake for everything I eat.
My google-fu has failed me and I absolutely cannot find calorie value information on spent coffee grounds. I can find coffee beans (whole / unused) and I repeatedly find that black brewed coffee has negligible calorie content, but nowhere do I find the calorie values for used / spent coffee grounds.
Anyone know where I can source this data?
This paper (PDF warning) suggests that dry spent coffee grounds contain about 60% fiber, 17% digestible carbohydrates, 17% protein, 2.5% fat, and 1.3% mineral ash content. Based on the rules of thumb for calories (4 calories/gram for proteins/carbs, 9 calories/gram of fat), that's roughly 160 kcal/100 grams dry coffee grounds. [This is a back-of-the-envelope rough estimate, not gospel.]
Thank you!
You found a whitepaper specifically for spent coffee grounds. Thank you so much.
As for the back-of-the-envelope figure, hey, it's the best I've heard so far that shows what the number is being based on.
Note - I got the "digestible carbohydrates" number by adding up the cellulose/hemicellulose/lignin fractions and subtracting "total dietary fiber".
There's some debate about whether fiber is actually completely indigestible, or whether digestive flora make any caloric content available. I'd still say that spent coffee grounds are a healthy nutritional additive, especially with the relatively high protein content since coffee beans are seeds.
I'm curious about the results of your substitutions in baked goods - please let us know!
First test results are in. I've made myself very mildly sick and know to use lower amounts next time.
I used fresh coffee grounds (not brewed) since I wanted to experiment but I didn't have spent grounds ready.
Basically I tried making mocha oatmeal. I've made an oatmeal variant before that is a base of oatmeal cooked with water and then I mix vanilla yogurt in after cooking - that mix is fine. In this case I added 20g coffee and 6g unsweetened cocoa cooked into the oatmeal - this was definitely too much of both of those ingredients for taste and too much coffee in terms of caffeine content. I stopped eating after consuming 1/3rd of what I made and can tell I am experiencing mild caffeine overdose.
When I try making it again I'll probably leave out the cocoa and use 4g of coffee with the same amount of oatmeal and yogurt. I'll also skip my 2nd cup of coffee on the day I want to try it.
Coffee grounds are fairly indigestible; I would expect that most of the benefit of coffee grounds in other foods would be the inclusion of indigestible fiber. You may get some degree of additional extraction in the gut, but humans aren't really built to extract nutrients from seeds without extensive processing.
Spent coffee ground has a calorific value of ≈47 kcal/kg (19.74 MJ/kg), so it's virtually negligible even if that were assumed to be fully digestible.
If the coffee has negligible calories, why would you expect the grounds to change? I don't believe there's any chemical reaction occuring.
The extraction process may not extract any calories. Barley tea, for instance, is considered to have 0 calories, at least on food labels, but certainly barley has calories.
That being said, I'm somewhat doubtful humans can even digest coffee grounds, let alone get non-neglible calories from.
Are you from the US by any chance? Because I know of several instances where companies there are allowed to round down the calories count to 0, even when it's not truly 0 calories. Tic-tacs, for instance.
I decided to look this up out of curiosity. The rules vary by nutrient; I only checked added sugars.
Generally speaking, the nutrition label must contain "Includes `X' g Added Sugars". X may be zero if there are less than 0.5g of added sugars (so your example isn't quite right). It can also read "less than 1 gram" (if that's accurate).
Under some circumstances, that label is not required, but instead the statement "Not a significant source of added sugars" must be included below the nutrition tables. Oddly enough, that statement means "less than 1 gram" when the Standard Format tables are used, and "less than 0.5 grams" when the Simplified Format is permitted and used. I suspect this discrepancy is a bug.
(If there are at least eight nutrients listed in the "Not a significant source" list (six for infants, toddlers, or RoboCop), it's probably the Simplified Format).
In the end, it makes sense to have some cutoff, and I don't see 0.5 grams (that bug notwithstanding) as being an unreasonable one (1% of DV).
References below
Standard Format
21 CFR 101.9(c)(6)(iii)
Simplified Format
21 CFR 101.9(f)
I also briefly checked Calories—less than five may be expressed as zero (so 0.25% of a 2000 Calorie daily intake).
That trick is mostly applicable where you can get away with small serving sizes, e.g if you make a serving size exactly 1 tic-tac then the flat cutoff for when you can call something 0 calories can be "abused". But that's not really applicable to a 16oz bottle of barley tea, which at most manufacturers split into two servings, and most of which are made in Asia and imported anyway.
I'm not sure how it would be calculated for different brewing methods, but I brew with a french press and skim the top off (which has foam and, importantly, oils).
Oil will be energy dense and I'm removing a fair bit of that (though presumably not all), thus changing the calorie content. Really not sure how to account for this, although your inference that if the liquid coffee has negligible calories then I could conclude otherwise negligible reduction in calories from the grounds is logical (if not accounting for the removed oils).
Thank you for the perspective, it is helpful.
The amount of oil you're skimming off is like fractions of a gram. That bloom is mostly trapped CO2 from the roasting process being released into the liquid and being trapped again by the holes in the coffee beans.
During the coffee roasting process, I imagine most of anything that would produce a calorie is burned off. While there would be calories in the spend ground... I doubt your body can digest them. It's like 90% cellulose I imagine. Your body will just pass it through.
When you add coffee grounds to something to bake, it's usually not spent grounds, and they will add no flavour, just an unchewable texture. Coffee grounds are usually added for that texture, but also for the coffee flavour. Not spent ones.
Relevant, and quite a fair point. Sometimes I get over-focused on a detail and forget to consider the whole. Thank you.