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pacayaforhops · 02-01-2012, 03:15 AM

how about brewing hops tea side by side with rosa de jamaica/saril/hibiscus and comparing IBU's that you can plug into the software 1 12 oz glass~1/16 of a gallon

**Curtis2010** · 02-01-2012, 01:43 PM

Good empirical idea for approximating.

Any idea how bitterness is actually measured in the lab?

pacayaforhops · 02-03-2012, 03:36 AM

from http://beer.wikia.com/wiki/International_Bitterness_Units :

A formula craft brewers use to calculate IBU is:

Wh × AA% × Uaa ⁄ ( Vw × 1.34 ), where

Wh refers to the weight of the hops used, in ounces
AA% refers to the alpha acid percentage, which is influenced by many factors, including cultivation method, species, and time of year — hops are often sold labeled with this percentage
Uaa is the percentage of alpha acid that is actually used during the boiling process
Vw means the volume of the wort, in gallons
1.34 is a constant factor that adjusts the measurement to account for the use of U.S. customary units

from http://www.sizes.com/units/international_bitterness_unit.htm :
An equation. IBU equal a fraction. The denominator is 0.3. The numerator is A plus the fraction B over 9.

where

H is the concentration of hops in grams per liter.
A is the concentration of alpha acids in the hops, expressed as a percentage.
B is the concentration of beta acids in the hops, expressed as a percentage.

Of the 2, the 1st is the more accurate. I just use http://powersbrewery.home.comcast.net/~powersbrewery/mastercalculator.html and plug in the AA% values and boil times.

**Curtis2010** · 02-03-2012, 01:02 PM

Thanks for the info. Unfortunately w/out AA info (if any) for Rosa Jamaica I won't be able to calculate IBU's, but I suppose if I could find a similar bitterness hops then I could approximate.

**Curtis2010** · 02-03-2012, 01:22 PM

I've been brewing some really good beers here in the tropics (Belize & Guatemala), most of them at ambient temps (often 80-90F !) in the summer (my off season), for about 6 years now. My luck with high-temp fermentation was bound to run out sometime.....and yesterday was the day.

I was brewing what I anticipated to be a very nice IPA...the wort tasted fine...quick vigorous stat to ferm...the smell during fermentation was delicious...but the wort taste near completion of primary fermentation was awful. We have had a relatively cool (70-80F) Dec-Feb so I was not expecting any issues, but the off-flavor is so powerful that it even completely masks the intense hops of an IPA. No obvious signs of bacterial contamination -- the wort itself looks fine.

In this batch I was using a yeast strain for the first time: Safale (Fermentis) US-05. Does anyone have experience with this yeast?

**unionrdr** · 02-03-2012, 01:33 PM

The safale US-05 is good between 57-70F. It's a clean fermenting yeast with little or no flavors coming from it. Re-hydrating is good with any dry yeast,but this one does well sprinkled on dry. I prefer re-hydrating for shorter lag time.

pacayaforhops · 02-03-2012, 01:59 PM

Can you describe the off taste? I made a spiced porter 2 years ago that smelled like (and tasted like) firecracker smoke until I cold conditioned for a couple of weeks and the yeast dropped out of suspension, then it tasted like it was supposed to (used Wyeast irish ale though), there is still hope for it.

**Curtis2010** · 02-03-2012, 02:11 PM

Quote:

Originally Posted by unionrdr

The safale US-05 is good between 57-70F. It's a clean fermenting yeast with little or no flavors coming from it. Re-hydrating is good with any dry yeast,but this one does well sprinkled on dry. I prefer re-hydrating for shorter lag time.

Yes, this is consistent with what I have read this AM on US-05. The spec sheet from Fermentis gives the upper temp range as 75F so I was not much over that range, but of course a few degrees could make a big diff.

I prepared the yeast by first rehydrating and then pitching to a 1 liter starter (out of habit) a few hours before pitching to wort. This would obviously give me a much higher cell count, but I don't think it would have adversely effected the flavor. Also, this was a relatively HG brew at 1.070 so a higher pitching rate would be appropriate anyway. Starter was fermenting vigorously when I pitched it and the wort got off to a grand start (had to rig a blow-off tube). Primary had slowed dramatically by day 4.

However, after reading Fermentis' recommend process (rehydrate only) I may not bother with the starter in the future.

I have read in other reviews that the yeast does not flocculate well. This could certainly effect the taste of the wort sample, which visibly had lots of yeast in it. But, I think this is wishful thinking on my part....it did not taste like yeast, but more of what I understand phenols to taste like (never have specifically had the opportunity to taste test)...like the wort was spiked with nail polish remover!

**unionrdr** · 02-03-2012, 02:21 PM

Could be a combination of high temps & using it in a starter. I made starters with cooper's ale yeast,but pitched the US-05 dry or re-hydrated. Something about the cell walls of the yeast absorbing a heavier liquid than just water. It is said to make for a lower cell count do to supposedly weakening the cell walls. Kind of like stressing the yeast. But in my experience it did work fairly well. Rehydrating has proven to be a bit better with dry yeast.

pacayaforhops · 02-03-2012, 04:27 PM

Quote:

Originally Posted by Curtis2010

it did not taste like yeast, but more of what I understand phenols to taste like (never have specifically had the opportunity to taste test)...like the wort was spiked with nail polish remover!

Sounds more like acetone/acetaldehyde, the yeast should clean it up after a couple of weeks conditioning if you let it sit on the yeast cake. Phenols smell like clove/spices in the best of cases or (burnt) plastic in the worst.

You should let it sit for a few more weeks anyway. I'd recommend 3-4 weeks primary for ales over 1.060 OG, it's worked well for me with my stout and weizenbock, the first made with wyeast irish ale, the second with wyeast kolsch yeast (had some serious banana going on in the later).

You could also purge it with CO2 once you have it kegged, carb to 60 PSI @ 40*F over the weekend and then let the gas come out through the relief valve until the foam hits it, let sit until the foam dies down and repeat until you're at 10 PSI or the smell is acceptable. I had to do that with a steam beer that came out with too much, wouldn't you know it, phenol (clove); one of my best beers so far once the phenol was dialed down.