1 Posted: Sunday, March 19, 2017 11:42 PM

Hi all,

I often use the APA kit as a base for my brews and want to increase the IBUs a bit with a short boil (<20 minutes) of finishing hops. I tend to use a 1L pot and my volume is often just 500-750mL. If I am using specialty grains, I will use the grain tea for the boil (no idea of the gravity). If I am not using specialty grains I will boil in plain water. Quite often I find the resulting bitterness of my brew quite harsh. I wonder what I am doing wrong? Is this because I am boiling in water? Should I be mixing up a small amount of wort with a known SG, like 1.040?

Does anyone know if Ian's Spreadsheet assumes you are using 1.040 wort for the boil, which is what it looks like? Are the IBU calculations completely inaccurate if one boils in water? And what exactly does the HCF toggle do? Should I turn it on or off? I notice IBUs look much higher if it is off, which seems to be the default.



2 Posted: Sunday, March 19, 2017 11:49 PM

Just partly answered my own question. Yes, Ian's spreadsheet does want you to use a wort with SG 1.040: the amount of DME recommended changes depending on which specialty grains you have entered. Geez, I never noticed that before, and I've never added DME to the grain tea. I feel so dumb. That might explain some of the harshness I've noticed, as the lower the gravity, the greater the extraction.

Guess I will be changing the volume to what I actually use, and will start adding DME to the grain tea or water to bring it to 1.040. No more boiling in plain water.

But I am still lost on the HCF. Anyone?



3 Posted: Monday, March 20, 2017 12:08 AM


But I am still lost on the HCF. Anyone?

Oh, I might have figured this out too. You turn HCF on if the gravity (and volume) of your specialty grain tea is such that the spreadsheet recommends a negative amount of DME be added. Is that right? The alternative would be to add more water to the grain tea, to make the recommended amount of DME needed zero….It would have been nice if that had been spelled out somewhere.



4 Posted: Monday, March 20, 2017 12:21 AM

Nope, what I said above is wrong. Even if I adjust the volume so that the recommended amount of DME is zero, the IBU rating changes when I toggle the HCF between on and off (higher when it is off). I really don't understand, and I am getting frustrated.

I suppose other factors could also be increasing my perceived bitterness, like pH and tannins….I tend to use my well water, which is a bit hard (pH 7.8). Apparently high pH = high utilization, low pH = low utilization.



5 Posted: Monday, March 20, 2017 6:13 AM

The HCF is to do with small volume boils supposedly not contributing as many IBUs for the same amount of hops as a larger boil would. I don't know whether it does or doesn't, but I do know that when I brewed extract with small volume boils I always had the HCF turned on, and the finished beer definitely seemed to line up with the IBU rating. With it turned off as you say the IBU rating was a fair bit higher, and the beers just weren't that bitter.

I suppose it helped that I began doing full volume AG boils soon after that, so I did have something to compare it to.

6 Posted: Monday, March 20, 2017 6:35 AM

Hi Christina, I quite enjoyed reading your monologue this morning!

I've always used the HCF on when using IanH ‘s spreadsheet. I have read before that the bigger the boil, the better. I used to boil 9L of wort (adding the right amount of LME or DME) as recommended by the spreadsheet.

Have since upgraded to a cauldron and did a full-volume extract boil on Sat night.

Interestingly, the HCF on a 25L boil was still 1.13. I don’t understand the numbers TBH. But given scaling up from 9L to 25L boil, I used less hops to hit the target IBUs.

Proof will be in the glass in about 4 weeks time!

7 Posted: Monday, March 20, 2017 6:49 AM

Hi Joolbag.


Hi Christina, I quite enjoyed reading your monologue this morning!

One of the disadvantages to living on the opposite side of the world: nobody on the forum is awake when I am. LOL!

Congratulations on your new cauldron and first full volume boil. Hope your brew turns out awesome.


I used to boil 9L of wort (adding the right amount of LME or DME) as recommended by the spreadsheet.

Where does the spreadsheet recommend 9L of wort for hop boils? I don't see that anywhere, and my version defaults to 1L.

Nine liters is a pretty large volume. That would be hard to cool down just by mixing with cold tap water, or even refrigerated water, wouldn't it?



8 Posted: Monday, March 20, 2017 7:42 AM

I recall reading quite some time ago when I was using this technique that a hop tea made in water alone produced a harsh kind of bitterness. I therefore used to steep grains (30 mins) and then boil that ‘malt tea’ with any bittering/flavouring hops I required. I usually added around 500g of LME to get my SG up to around 1.040. Sometimes if I just wanted a bit of hop aroma and added flavour I'd simply steep the hops along with the grains. I always had HCF turned on when I was using the spreadsheet.


Nine liters is a pretty large volume. That would be hard to cool down just by mixing with cold tap water, or even refrigerated water, wouldn't it?

I place my 11 litre pot in a sink full of cold water which I further cool by draining the water and refilling a few times. This drags the temp of my 9 litres of wort down reasonably quickly. By the time I'd topped my FV up to volume with pre-chilled water it is at pitchable temperature - perhaps 30 minutes all up.

9 Posted: Monday, March 20, 2017 8:27 AM

If you plan ahead and pre boil and then freeze water you can add your sterile ice to the FV to further decrease chilling times and get to pitching temps faster

10 Posted: Monday, March 20, 2017 12:44 PM

Sorry Christina, rushed the post and put parentheses in the wrong spot! Was getting the kids ready for day care and managed to quickly log into the forum and bung out a couple of replies.

It should have read:

I used to boil 9L of wort (adding the right amount of LME or DME as recommended by the spreadsheet.)

The spreadsheet version I use has a 2nd tab called “brewday” which is rather fantastic! It tells me how much LME or DME to add to my boil volume to bring it up to 1.040. It is also on the first page. near the bottom. This is the number I was referring to in my post.

To answer your question about cooling - well Blacksands and Mark D Pirate have done it. Chilled water and/or ice frozen in sanitised takeaway containers.

How much of each to add to get it to pitching temp? Easily calculated using an online calculator like http://www.onlineconversion.com/mixing_water.htm.

Now that I am only doing full-volume boils, no-chill, I won't be using this calculator again. Oh wait, I have two Coopers kits in my inventory, so just for those two brews. And you bet that for those I will be pre-treating my water with Campden tablets! Any water that ends up in my brew is going to be treated to remove chloramines from now on.

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11 Posted: Tuesday, March 21, 2017 12:23 PM

Hi Christina.

I too enjoyed reading your monologue at the start of the thread!

Along the bottom in IanH's spreadsheet you'll see a number of tabs relating to different areas of the spreadsheet. On the far right, you'll see the “Notes” tab. click that, & IanH has provided a small guide to how the spreadsheet works etc.

If you plan to start boiling hops regularly, I would suggest you look to begin with a wort of at least 5 litres. The 1.040 SG for the beginning of the boil is simply a uniform number that has emerged by home brewers so that we can ‘compare apples with apples’ when problem solving & discussing our brews. i.e. If we all use the same SG wort that eliminates one area as a potential point of difference or problem.

Cooling the wort is easy. Simply place the pot in a sink & surround it with cold tap water. After about 10-15mins the wort inside the pot & the water outside it will have equalized & will still be quite warm to hot. Empty the water in the sink & surround the pot again with cold tap water. After another 15-20mins it should have cooled to a reasonable temperature that you can strain it into your fermenter, then add the rest of your ingredients & cold water to attain a suitable yeast pitching temperature.

The HCF (Hop Concentration Factor) simply allows you switch between calculating the IBU of your recipe in either “Tinseth” (the most widely accepted & used formula) or “Garetz”. As Kelsey said, Garetz theory takes boil volume into consideration when calculating the IBU, whereas Tinseth does not, hence the different numbers they spit.

I did a lot of reading about Garetz formula for IBU calculation to understand it. Garetz theory was primarily built on the back of low alpha “noble” type hops where a lot of weight was required to produce certain higher bitterness levels. With the advent of many new world high alpha varieties, this is no longer an issue.

I've found that provided you don't overcrowd the boil with too much hop matter, you can easily use Tinseth for your IBU calculation & know that it will be very close, if not the same IBU that would be created in a full volume boil.

Using wort rather than water softens the bitterness created when boiling hops. The higher the SG of the wort, the softer the bitterness produced due to a sliding scale of decreased utilisation as the SG rises. Steeping hops for flavour & aroma in water at a temperature below 80°C is fine as you are not isomerizing the alpha acids as you do in a boil. Around 65-70°C is a good temp range to work in.

I hope that helps some.


Last edited by Beerlust (Tuesday, March 21, 2017 12:23 PM)