The caffeine in coffee stimulates the production of irritating acid

Question

The caffeine in coffee stimulates the production of irritating acid in the stomach. But darker roast s of coffee, produced by roasting the coffee beans longer, contain more N-met hylpyridinium (NMP) than lighter roast s, an d NMP tends to suppress production of acid in the stomach. Therefore if you drink caffeinated coffee, darker roast s will irritate your stomach less than lighter roasts.

The answer to which one of the following questions most helps in evaluating the argument ?

(A) Does extending the roasting time of coffee beans increase the amount of caffeine present in the brewed coffee?
(B) Does a reduction in acid production in the stomach have an adverse effect on stomach function ?
(C) Would coffee drinkers who drink caffeinated coffee increase their coffee consumption if the coffee they drank contained less caffeine?
(D) Do some coffee drinkers who switch from lighter to darker roasts of coffee increase their daily coffee consumption?
(E) Do lighter roasts of coffee have any important health benefits that darker roasts of coffee lack?
 
Source: LSAT

GYANENDRA88 · Answer

A is the correct choice
Caffeine stimulates acid production.
If on roasting amount of caffeine increases then it will nullify the effect of increased amount of NMP.

Posted from my mobile device

RiyaJ0032 · Answer

how do you know this?

where is it given that the caffeine will "nullify" the NMP?

This is an unverified assumption

can some expert help?

Bunuel 
 MartyMurray 
 GMATNinja

Krunaal · Answer

Let us say I drink 1 cup of lighter roast coffee that contains 100 mg caffeine, now suppose 100 mg of caffeine produces 2ml of irritating acid in my stomach without NMP, due to some NMP only 1ml actually gets produced.

Now, if I roast the coffee longer and have 1 cup of dark roast coffee - let's say the roasting process did not increase caffeine quantity but increased NMP - 100 mg caffeine will now only produce 0.5ml of irritating acid instead of 1 ml due to higher NMP.  It's good for my stomach.

But let's say, due to roasting that 100mg caffeine became 200mg, even with the strengthened NMP it will still produce 1ml of irritating acid = the same as it was for light roast at 100mg caffeine.  No benefit for my stomach.  Higher NMP still did its work of suppressing but due to higher caffeine in 1 cup, acid stimulation increased.

Hope it helps.

MartyMurray · Answer

The caffeine in coffee stimulates the production of irritating acid in the stomach. But darker roasts of coffee, produced by roasting the coffee beans longer, contain more N-methylpyridinium (NMP) than lighter roasts, and NMP tends to suppress production of acid in the stomach. Therefore if you drink caffeinated coffee, darker roasts will irritate your stomach less than lighter roasts.

The conclusion of the argument is the following:

if you drink caffeinated coffee, darker roasts will irritate your stomach less than lighter roasts

The support for the conclusion is the following:

darker roasts of coffee, produced by roasting the coffee beans longer, contain more N-methylpyridinium (NMP) than lighter roasts, and NMP tends to suppress production of acid in the stomach

So, the reasoning of the argument is basically that, since darker roasts contain more NMP than lighter roasts, darker roasts will irritate your stomach less than lighter roasts because the greater amount of NMP in darker roasts will do more to counteract the acid-production-stimulating effect of the caffeine.

The answer to which one of the following questions most helps in evaluating the argument?

This is an Evaluate question, and the correct answer will be the choice such that an answer to the question presented by the choice will weaken or strengthen the argument.

(A) Does extending the roasting time of coffee beans increase the amount of caffeine present in the brewed coffee?

This choice is interesting.

The passage indicates that "caffeine in coffee stimulates the production of irritating acid in the stomach."

It then says that darker roast coffee contains more NMP, a substance that counteracts the effect of caffeine because NMP "tends to suppress the production of acid."

But what if the answer to this question is "Yes," and extending the roasting time of coffee beans does increase the amount of caffeine present in the brewed coffee.

In that case, darker roast coffee not only contains more NMP, which tends to suppress production of acid, but also contains more caffeine, which stimulates production of acid.

So, in that case, it's not clear that darker roast coffee is less irritating since the acid-production-stimulating effect of the additional caffeine in darker roast coffee offsets the acid-production-suppressing effect of the additional NMP.

Thus, a "Yes" answer to this question casts doubt on the conclusion.

Also, a "No" answer to this question helps to support the conclusion by serving to rule out the possibility that there's additional caffeine in darker roast coffee that will make it just as irritating as lighter roasts even though it contains more NMP than lighter roasts.

So, since different answers to this question weaken or strengthen the argument, the answer to this question helps in evaluating the argument.

Keep.

(B) Does a reduction in acid production in the stomach have an adverse effect on stomach function?

Neither a "Yes" nor a "No" answer to this question weakens or strengthens the argument since the conclusion of the argument is not about "stomach" function.

In other words, since the effect on stomach function of a reduction in acid doesn't affect how much irritating acid is produced, the answer to this question has no effect on the argument.

Eliminate.

(C) Would coffee drinkers who drink caffeinated coffee increase their coffee consumption if the coffee they drank contained less caffeine?

The answer to this question has no effect on the argument.

After all, the argument is about darker and lighter roasts of coffee, not about coffee that contains more or less caffeine.

Regardless of whether people would drink more coffee if the coffee they drank contained less caffeine, darker roast coffee may be less irritating.

Eliminate.

(D) Do some coffee drinkers who switch from lighter to darker roasts of coffee increase their daily coffee consumption?

This choice is a tricky because the answer could seem to weaken or strengthen the case for the conclusion.

After all, presumably, increasing coffee consumption will result in increased stomach irritation. So, we could get the impression that this choice is correct because a "Yes" answer to this question means that drinking a darker roast of coffee may result in just as much irritation as drinking a lighter roast because people will drink more of a darker roast. So, a "Yes" answer to this choice could seem to weaken the case for the conclusion of the argument.

At the same time, this choice is not correct for the following reason.

The conclusion is not that, in general, people drinking darker roasts of coffee will experience less stomach irritation. The conclusion is "if you drink caffeinated coffee, darker roasts will irritate your stomach less than lighter roasts."

So, the conclusion is about what a darker roast itself does. It's not about how much stomach irritation people who drink each type of coffee can be expected to experience. In other words, the point is that darker roast coffee is less irritating. It's not that all people who drink darker roast coffee have less irritation.

Maybe some people who switch to darker roast coffee drink more and experience increased irritation, but that outcome doesn't occur because darker roast coffee is more irritating. It occurs because some people drink more of it.

So, information on whether people who switch from darker to lighter roasts increase their coffee consumption has no effect on the argument because that information does not indicate how the irritation caused by darker roast coffee compares with that caused by lighter roast coffee.

Eliminate.

(E) Do lighter roasts of coffee have any important health benefits that darker roasts of coffee lack?

The answer to this question neither weakens nor strengthens the argument because the conclusion of the argument is not about "health benefits." It's simply about how much coffee will "irritate your stomach."

So, information health benefits does not have an effect on the case for the conclusion.

Eliminate.

Correct answer:   A

RiyaJ0032 · Answer

Hi  MartyMurray

Thanks for your explanantion!

However, I wanted to know that -

"since the acid-production-stimulating effect of the additional caffeine in darker roast coffee offsets the acid-production-suppressing effect of the additional NMP"

Why have you assumed that with more caffeine, the acid production OFFSETS effect of NMP

where is this given?

Choosing this option hinges on us assuming that more caffeine would 'offset' the effect of NMP 
 but it can be that although more caffeine would lead to acid production, NMP would suppress the effect of whatever amount of acid is produced by the caffeine

MartyMurray · Answer

Hi Riya.

Actually, for choice (A) to work, we don't have to assume that more caffeine would definitely completely offset the effect of the additional NMP in darker roast coffee.

A weakener doesn't have to PROVE the conclusion incorrect by indicating something with such certainty.

Rather, a weakener just has to CAST DOUBT on the conclusion or undermine the support the evidence provides for the conclusion.

In this case, a "Yes" answer to choice (A) does undermine the support provided by the evidence. It does so by indicating that, while the additional NMP in darker roast coffee suppresses the production of acid, darker roast coffee MAY not be less irritating than lighter roast coffee because darker roast coffee contains more caffeine.

So, though, as you suggested, a "Yes" answer to (A) does not necessarily mean that darker roast coffee is not less irritating, a "Yes" answer does cast doubt on that conclusion.

Thus, the answer to (A) helps with evaluating the argument.

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The caffeine in coffee stimulates the production of irritating acid

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The caffeine in coffee stimulates the production of irritating acid

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