If one does not understand the process involved in creating a granola bar, one could study the ingredient panel a hundred times and still not be able to answer the above question. However, through our access to the companies that produce these bars we are privy to information that is important in resolving this issue.
In the late nineteenth century “Granola” was a trademark for foods consisting of whole grains that were crumbled and baked until crispy. Today, granola bars are made from whole grain oats that are first cooked until softened and then rolled into flat flakes. They are then combined with sugars, oils and syrups and baked. The Mishna Berura (Orach Chaim 208:3) states that if grains are reduced and broken down in the cooking process, even if they were introduced whole, one should recite Mezonos. The granola bar grains appear to remain whole. The Shulchan Aruch (Orach Chaim 208:4) says that on whole toasted grains the proper Beracha is Borei Pri Hoadoma. In many granola bars the oats actually comprise less than fifty percent of the volume of the bar. The majority of the ingredients are those on which one would recite a Shehakol. Never the less, Rabbi Belsky and Rabbi Schachter have said that the proper Beracha Rishona to be recited when eating a granola bar is Borei Pri Haodoma. The oats (granola) are clearly considered the ikar, and all the other ingredients are considered tofel. We should therefore follow the regular rules of ikar vitofel and recite Hoadoma. Some poskim, however, consider the cooking process together with the subsequent baking to be a maiseh kideira. They posit that through all the cooking and baking, the grains must be partially broken down, and the proper beracha to be recited, as per the above mentioned Mishna Berura, would be Mezonos. Whether one recites Haodoma or Mezonos either way one would be yotzai bidieved. The disagreement is as to which beracha should be recited lichatchila.
The Shulchan Aruch (Orach Chaim 208:4) quotes the opinion of the Rambam that the beracha achrona for toasted grains is Borei Nifashos. However, the Shulchan Aruch also brings that Tosfos was uncertain as to whether a special Beracha achrona, Al Haodoma V’al Pri Haodama, should be recited. Since there is no mention of such a beracha in the Gemara, Tosfos leaves the matter unresolved, and suggests that one who wishes to eat these foods should do so only in the context of a meal. This way it will be covered by Birchas Hamazon. If one already ate toasted whole grains, one has no choice but to say a Borei Nifashos. Ideally, one should not bring oneself into such a situation. Accordingly, if one wishes to eat a granola bar, one should first wash nitilas yadayim, eat a slice of bread, and then eat the granola bar. Don’t forget to bentch at the end. This sounds like a long way to have to go to enjoy a quick snack. Perhaps there is an easier solution.
If one eats an amount equal to the volume of a zayis (an olive), toch kdai achilas pras (in the time it takes to eat 8 kezaisim) then one is required to say a beracha achrona. If one eats slower than this pace, then one does not recite a beracha achrona. What if one eats more than a kezayis of a granola bar bichdei achilas pras but eats less than a kezayis of oats. The Mishna Berura (Orach Chaim 210:1) says that in such a scenario the oats would combine with the other ingredients to obligate one in the berachah achrona of Borei Nifashos, and he would not be obligated in any other beracha achrona.
Now all we must do is measure how many kezaysim of oats are in a granola bar, and make sure to eat less than a kezayis of them in a kdei achilas pras.
The amount of oats by weight in a Nature Valley granola bar is about 50%. The serving size is 2 bars, which is 42g. This means that one serving contains 21g of oats. However, grams are measures of weight and kezaysim are measures of volume. For halachic purposes we must convert from weight into volume. The bulk specific density of rolled oats is approximately .304 g/cc (.304 grams per cubic centimeter). Therefore, 21g of rolled oats take up the volume of 69 cc. However, bulk specific density includes all the air spaces trapped between the oats. For our purposes, we must exclude all those air pockets and measure the volume of just the oats.
To measure the volume of just the oats, One can devise the following experiment. Fill a measuring cup with 2 oz. (1/4 cup) of oats and add 4 oz. (1/2 cup) water. The water and the oats together should fill 6/8 of a cup. However, the resulting mixture will fill only 5 oz. (5/8 cup). We see that the airspaces between the oats puff the oats to twice their true volume, so that 2 oz. of oats in reality only takes up 1 oz. of volume. Our 69 cc of oats in a serving size of 2 granola bars in reality only comprise 34.5 cc of true volume. Thus one granola bar would contain 17.25 cc of oats.
There is a dispute amongst the Rishonim as to how to measure the size of a kezayis. It is either half a kibaya or one third. Rabbi Belsky and Rabbi Schachter both agreed that in this situation we could be lenient and accept the larger size kezayis for evaluating our granola bar. According to Rav Chaim Naeh this larger kezayis equals 27 cc. Converting back into granola bar units at 17.25 cc of oats per bar, this is slightly more than 1 ½ Nature Valley granola bars. Based on the above as long as one consumes less than 1 ½ granola bars every kdei achilas pras, one has avoided the safek of Tosfos.
How long is kdei achilas pras? Rabbi Schachter explained that each food is evaluated according to the normal length of time it takes to eat 8 kezaysim of that product. Rabbi Schachter approximated that it would take an average person about 2 minutes to consume 8 kezaysim of granola bar. Rav Belsky was uncertain but said it would certainly be less than 5 minutes.
In conclusion, if a person consumed 2 granola bars in less than 2 minutes, he has no choice but to recite a Borei Nifashos. Ideally though, one should either plan to eat less than 1 ½ Nature Valley granola bars every 2-5 minutes and then recite a Borei Nifashos, or plan on eating lots of bread.