Inconsistent/insufficient bitterness and hop flavor

I made the following 2.5 gallon batch:

5 lbs floor malted pilsner malt
0.5 lb Carapils
0.75 oz Saaz (60 mins)
0.75 oz Saaz (15 mins)
0.75 oz Saaz (5 mins)

I tasted it last night and it's not carbonated yet, but it does not taste at all bitter or hoppy despite calculating to 40 IBU.

I believe I attained an adequate boil.

I used about 35% filtered water, 65% tap water. I don't know what my tap water is like but I tempered it with some filtered water based on the suspicion that Floridian tap water is typically hard.

My last batch of beer was extract and used only used 1/2 oz of Perle and 1/2 oz of Hallertauer and yet it seemed to have superior bitterness and flavor to this one. But I've also been disappointed with the hopping of some of my beers in the past.

What am I doing wrong?

Edited to add: pellet hops.

 

Each year there is a variation in the alpha acids of the hops as the weather changes from year to year where they are grown. You may have designed the recipe for Saaz with 4.3% alpha acid and got hops that were only 1.7% Check your hop lables carefully as this year had some hops with low alpha acid which gives you low bittering.

 

Thanks RM-MN, that brings up a good point. My LHBS scoops from a big bucket and does not specify alpha acid percentage on their site, so they could be old and weak.

The beer's still pretty good.

I may have to try some of my same recipes with hops from a reputable online retailer.

 

They just have hops sitting there in a bucket?

 

yikes! that would definitely do it. Hops should be stored in an oxygen barrier package, cool and dry

 

yeah that sounds like a pretty ****ty place to buy hops from!

i will also add that the more it carbonates, the more perceived bitterness will go up. i've had ipas that i thought weren't very bitter at all, because i tried it at 2 weeks in the bottle. comparing that perceived bitterness (in my mind) at 3 weeks, 4 weeks, and 5 weeks, and it seemed to continue to go up as it aged a little. from about 5 weeks and on it typically stays the same.

also, i decided to type your recipe into beersmith. i selected BIAB light body, selected just the stock profile for saaz (3.75%) and got:
og - 1.058
fg - 1.010
ibu - 30.9
ebc - 4.7

so not sure where you got 40 ibus from. i just bought some saaz from my lhbs that came at 3.6% aa. which would bring the ibus down to 29.7. not much, but still much lower than you're calculating. add on top of that the 1.058 and you're looking at a not very bitter beer. the low FG should help balance out some of the sweetness once it carbs up all the way, like i said, but don't expect it to be the same perceived bitterness level as 40 ibu.

even further, i don't ever go by just ibus to tell how much perceived bitterness i will have. i now go by this:
http://www.madalchemist.com/relative_bitterness.html

 

Perhaps not a bucket but a tupperware. I believe the hops are kept in a fridge.

The calculator I used was this one at Tastybrew.com.

joshesmusica: You raise another good point. I had been formulating my recipes recently based on 62% efficiency, which is what I got on the one and only batch that I tested gravity on. But perhaps that reading wasn't accurate or I got much better efficiency on this batch and that's why it's overwhelmingly malty.

Probably several factors conspired here. Thanks for all of the assistance.