Hop boil query

[stephenday1987]

Hi,

I was hoping someone confirm what seems in my head a very simple scenario but I don’t want to mess anything up!

I want to try brewing a Double IPA. I have a recipe all put together below than I’m going to attempt.

6.5lb Light Dried Malt Extract
0.6 lb (272 g) Crystal 45 malt
0.6 lb (272 g) Carapils Malt
0.75 lb (340 g) Corn sugar
3.50 oz (99 g) Columbus 13.90% A.A. 90 min.
0.75 oz (21 g) Columbus 13.90% A.A. 45 min.
1.00 oz (28 g) Simcoe 12.30% A.A. 30 min.
1.00 oz (28 g) Centennial 8.00% A.A. 0 min.
2.50 oz (71 g) Simcoe 12.30% A.A. 0 min.
1.25 oz (28 g) Columbus 13.90% A.A. Dry Hop
1.25 oz (28 g) Centennial 9.10% A.A. Dry Hop
1.25 oz (28 g) Simcoe 12.30% A.A. Dry Hop
US-05 Yeast

Basically my question is that I only have a smallish pot (about 2.5 gal) and so fear I am going to lose a lot of the IBU I extract in the boil by topping this up to 5 gal with water. However if I double the amount of hops going into the boil, then theoretically this will double the IBU’s and when diluting this down I should be at the 100 or so level than I am anticipating? Can anyone confirm this for me?

Thanks,

Steve

 

[Double_D]

Basically my question is that I only have a smallish pot (about 2.5 gal) and so fear I am going to lose a lot of the IBU I extract in the boil by topping this up to 5 gal with water. However if I double the amount of hops going into the boil, then theoretically this will double the IBU’s and when diluting this down I should be at the 100 or so level than I am anticipating? Can anyone confirm this for me?

It doesn't really work like this... If you're boiling a concentrated wort (partial boil) the extraction efficiency goes down drastically.

I'm not even sure how to properly explain the situation but I'm sure someone will chime in. I want to say I've read somewhere there is a saturation point for AA. Unfortunately, I'm not sure where to find it. Full boil is more efficient for extracting AA because the wort is less saturated with sugar, basically leaving more "room" in the water to absorb isomerized hop oil. Calculated IBU aren't always correct, especially on our scale.

I'd look to invest in a larger pot Those big IPAs are a good excuse to upgrade the brewing equipment IMO.

 

[stephenday1987]

Damn. Exactly what I was hoping you wouldn't say!

Thanks though, I'll have to do some googling and take a look into that. I'll probably have to put a hold on it and get a bigger pot at some point though by the looks of it.

 

[stephenday1987]

Thinking about it... I guess the other option is to do 2 small batches and combine them instead of topping up? You mention that the wort will still be more saturated and therefore extract less IBU's but I assume this will still be more efficient than simply throwing in some plain water and essentially diluting it down?

 

[Double_D]

I'd just go for it with your original hop schedule. Boiled in 2-2.5 gallons of water. It will be fine, maybe just not quite as much a hop bomb as you were going for.

 

[ncbrewer]

There is a limit to the IBU's that can dissolve - about 100 - 120. See http://byo.com/stories/issue/item/855-hopping-help-for-extract-brewers . "There is a limit to the amount of bitterness that can be imparted by boiling hops. Estimates of maximum hop bitterness range from 100–120 International Bittering Units (IBUs). Above this level, adding more hops in the boil does not result in more bitter beer. However, more bitterness could theoretically be obtained by adding hop extracts.

The solubility of (isomerized) alpha acids also varies with wort density — the denser the wort, the less alpha acids will dissolve into it. Given that most stovetop brewers boil a concentrated wort, wort density (measured by most homebrewers as specific gravity) frequently limits the amount of bitterness in their beers."

So you can only get 100 - 120 IBU max in the boil - diluting with the same amount of water will cut this to 50 - 60. Still not bad, but any hops added to raise above this limit would be wasted. Or as the article points out, you could use hop extract.

It should be noted that the limit based on wort gravity has been challenged in recent years. But that subject gets pretty involved.

 

[bigdaddybrew]

Boiling this much extract in a 2.5 gallon pot for 90 minutes is a lofty goal. Aside from the complicated IBU calculation I think the thicknness of the wort in the pot might be an issue. I bought a cheap stainless 5 gallon pot at my local dollar store for $20. I can gently boil 4 gallons of wort then top up. Later I bought two pots. This allowed me to use all 4 burners on my gas stove. Speeds up the boil and allows me a more vigorous full volume boil. I split the hops evenly between pots with good results. Might be time for a pot upgrade. Call grandma she might have a big pot she used for canning she can give you.

 

[Double_D]

I bought a cheap stainless 5 gallon pot at my local dollar store for $20. I can gently boil 4 gallons of wort then top up. Later I bought two pots. This allowed me to use all 4 burners on my gas stove. Speeds up the boil and allows me a more vigorous full volume boil. I split the hops evenly between pots with good results. Might be time for a pot upgrade. Call grandma she might have a big pot she used for canning she can give you.

This is what I meant, but hadn't had my coffee yet. I thought he was planning on 2 pots, or two boils.

 

[AlfA01]

I've never brewed an extract or partial mash beer, so I'm only offering some ideas that sprang into my mind when reading your post.

Brewing IMO as a preparation, has (for the most part) three steps: mash or partial mash, boil and ferment.

So, if I were in your situation, I'd boil my extract and place it in the fermenter. Then, steep the grains, bring to boil and add bittering hops. After that, follow whatever hop schedule and additional ingredient schedule you have.

Save a little of your extract boil, cool it in the freezer and then make a 'make shift' yeast starter based on your yeast packet rehydration instructions. Agitating often helps.

When you're all finished and the wort is cooled enough, pitch your starter and close up the fermenter.

As far as hop and bitterness saturation is concerned, I never use water in my beer that isn't boiled, in other words, I'm not a fan of topping up. Ph is a huge part of your brew. Adding unexposed and unboiled water will most definitely alter this, which will alter the effect your hops have on the beer.

Also, a DIPA is a big beer. Meaning, your post boil gravity should fall into the 1.070+ range. After you've boiled, and topped up, will you still have a DIPA? Or, a really hoppy IPA? Other factors will come into play there as well--that's why I suggested the 'make shift' yeast starter, as even a few hours will help you to revive those yeast to ensure you have enough cells to digest your sugars. Otherwise, you may have a slow or stuck fermentation.

Let us know if you decide to brew and how it turns out.

Cheers,
AlfA