Hop Extract calc makes no sense to me...

[Timmush]

Purchased a 150 gma can of Hop Extract to give it a try for bittering only.
63.7% alpha
I have a small system and use 1 lb of pellet hops to get approx 35 ibu's at 60 minutes.
Does anyone have any input on how much Extract to add to get the same results? The calculators I have been trying are giving me the strangest/varying results.

Thanks.

[Junkyard]

We used the calculator BSG provides to calculate bitterness on a 3bbl system. The value we got was way too high for the low bitterness we were tasting in the wort. Never did find out a calculator we thought was appropriate. We just use them to supplement bitterness in our DIPA's now any ways.

[dick murton]

Well if your normal hops have an alpha acid content of 6.37%, then the tinned extract alpha content is 10 times as concentrated, so you need to add 0.1 pounds extract instead of 1.0 pounds whole / pellet hops

[jebzter]

Your can is 150gmAA and it is 63.7% AA, which is 235.5g total weight. So you get 0.637g of AA for each gram of extract, we'll come back to this in a minute.

To figure out how much extract you need, you will need to know two things, the IBU contribution of the bittering hops and the volume of beer. This calc is the same way we figure out how much pellet hops to add. Extract tends to have about a 35% efficiency at 60 minutes(this is from YCH), so if you have a 35IBU beer in a 1 bbl system that is 35mg/L of AA, 1 bbl is 117.35L, so it would be 4.107g of AA in the whole batch, post boil and ferment. At 35% efficiency, that is 11.73g of AA dosed into the boil.

Your can is 0.637g AA/g of extract, so to get 11.73g AA from the can you need 18.41 grams of extract from the can.

[dick murton]

Jebzter - you're right. I misread the 150 as being 150 gramme weight tin, not the weight of AA. Cheers

[jebzter]

Today was our first use of extract for bittering, it went well, much better looking trub pile(the can was a 20% reduction in kettle load). There is one caveat we have found so far, the damn stuff sticks to the walls like no other. Its oily and dense, so hot water and caustic are required to remove it. Cold water only makes it stick more. Just an inconvenience, were working out a way to clean it better since doing a full CIP after each brew is generally not required or efficient.

[brain medicine]

temper the extract before you add it in. it seems to help with it getting into solution quickly before it sticks to kettle walls. either heat it up or pull some wort out and pre-mix before it goes into the kettle.

seemed to help alot for me.

[mmussen]

We've always hung the can in the kettle during run-off. That way the can gets nice and warm and the extract comes out of the can into the wort slowly (we just punch some holes in the top of the can we don't take the lid off)
That seems to help getting it into solution, but yeah, its a bitch to clean.

[jebzter]

We warmed the can, emptied the contents into a pitcher and then diluted it in hot wort before dosing. I may dilute it further. It was not a ton of stuff on the walls, just lots of little spots that didn't want to come off.