I have couple of coffee in my cabin where I visit on weekend and I saw 2 coffee which were best before xx 2017. One has big chunk of coffee and looks faded and the other got faded colour. I have no idea if it is instant or ground but namely one is Nescafé 
and other is 
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Neither looks like pure coffee... it might be instant or some coffee-drink-mix? (Or even the treasure of a four-yo that was diggin in the gravel?) What does the container say?– Stephie ♦Commented Oct 15, 2017 at 9:59
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First is Nescafé Alta Rica and other is kenco I cannot find what kind of coffee it is.– localhostCommented Oct 15, 2017 at 10:40
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I'm not sure to flag this as a duplicate of coffee.stackexchange.com/questions/2669/… as this is not coffee, but instant coffee.– MTSanCommented Oct 16, 2017 at 13:32
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1@MTSan not a dupe, imho. Will write an answer as soon as I have time.– Stephie ♦Commented Oct 17, 2017 at 6:24
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Technically Nescafe is coffee, its basically just coffee that's been brewed and dehydrated.– Evan NowakCommented Oct 22, 2017 at 4:22
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2 Answers
With all foods, FAT TOM is your best start to gauge their susceptibility to spoilage.
Now, FAT TOM is actually an acronym for the six factors that influence the growth of microbes. And bacterial growth is what causes food to turn bad in two senses, namely gross and dangerous, although the two often go hand in hand.
The factors are:
Food
Acidity
Time
Temperature
Oxygen
Moisture
In theory it's sufficient to eliminate just one factor to prevent spoilage, but in practical applications, it's often a combination of a few.
So for your coffee, the main factors are moisture, food and time.
For your Nescafé, the granules are dry, have very little "food" for pathogens (proteins are a real problem, for example) and are around or slightly past the best-before date1. If you say the coffe still tastes fine, I see no reason to suspect it to be unsafe.
I'm not sure about the second product, but will for now assume it's some kind of "cappuchino mix" that includes dry milk or another kind of creamer. My conclusion is largely the same as for the Nescafé product, but with a higher protein ("food") and possibly fat content. So you have a slightly higher risk of "spoilage", but it's not really about food safety, just rancidity and development of "off" flavours.
So to sum it up: If your instant coffee still tastes fine, dissolves as it should and was stored in reasonable conditions (dry, room temperature, closed container), there are no food safety concerns. You might want to use it within the next few months, though, but mainly due to quality reasons.
1 Another common misconception: "best before" does not indicate immediate spoilage after that date, it is a time by which the manufacturer assures you the product will be in excellent condition. This means also sensory attributes like taste or consistency. Plus there is always a safety margin included to be on the safe side, even if the consumer stores the product under less-than-ideal conditions. More on our sister site Seasoned Advice, for example here.
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How acidity affects spoilage? Is it better to store longer when the food is acidic? (Sometimes, we add citric acid as a conservative, right?)– MTSanCommented Oct 17, 2017 at 22:22
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1@MTSan yes, indeed. Just think of pickled gherkins or yogurt: two very traditional ways to make food last longer. Even fish (the epitome of quickly spoiling food) can be stored in a salty and acidic brine for weeks (but should be refrigerated).– Stephie ♦Commented Oct 18, 2017 at 4:12
Well, the second picture looks exactly like moldy Nescafe (plain instant coffee, should be brown). We had some on hand to replicate an apparently common Greek preparation based on it, made it a few times, lost interest, and forgot about it for quite a while. It got moldy, we threw it out. No idea about the first.
No idea why is seems to be prone to mold (I'd think instant coffee would be around for the cockroaches to drink after Armageddon) but that particular version does seem to.
