100% apparent attenuation in Tripel... surprising!

So I recently brewed a tripel with one of main goals being to really dry it out. I aimed to mash at 148-149, but over the course of 90 minutes, it dropped down to 146. OG was 1.070 (though calculated 1.091 after I added sugar 4 days into primary), and I pitched the yeast (WLP 530) from a gallon starter, and fermented at 64 for two days before ramping up the temperature over several days. I held it at 84 for 5 days (according to brew like a monk, and another good thread on here, this is common practice and works well as long as the first few days are cool). Before reaching the peak temp, I added 2.5 pound of sugar that I inverted on my stovetop, just after the peak of high krausen, in an effort to make sure that I got full attenuation. When I racked to secondary, it had been in primary a total of 9 days and had dropped from 1.091 to 1.010. I was very happy because the 88% apparent attenuation (AA) (which is 72% real attenuation) was what I had been shooting for. I left it in secondary around 60F for a month, and then bottled yesterday. I was very surprised upon bottling to check FG and find that it had dropped all the way down to 1.000, giving 100% AA and 81% real attenuation, weighing in at 12+% abv. The hydrometer sample was crystal clear, free of any fusels that I could detect, and smelled wonderful. Anyone surprised by this very high attenuation? Anyone have similar experiences with WLP 530? I'm not worried that anything is wrong, I'm just amazed. I've included my recipe below for information sake.

14 lbs continental pils
0.25 lbs aromatic malt
2.5 lbs inverted cane sugar (added on 4th day of primary)

t = 60, 2.25 oz tettnanger
t = 15, 1.00 oz saaz

Yeast: WLP 530 from 1 G starter

OG: 1.070 (without sugar)
calculated OG including sugar: 1.091

Simple sugars are a great attenuator.

I subbed out 1/2 pound each of flaked corn and rice for one pound of cane sugar. This along with a 147 mash temp for 90 minutes and my gravity hit 1.003 (down from 1043). Gonna be one dry crisp beer.

Congrats on a big beer.

Thanks, I hope it's as good when fully carbonated and served. I guess I was just shocked at that kind of attenuation for a beer that big.

Are you 100% sure that your hydrometer is calibrated correctly? It seems a little unlikely for a beer that big to ferment down to the density of pure water.

moti_mo said:

Are you 100% sure that your hydrometer is calibrated correctly? It seems a little unlikely for a beer that big to ferment down to the density of pure water.

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It's not that unlikely. There's a difference between "apparent" and "real" attenuation. Since ethanol has a lower specific gravity than water, 14% ABV beer with zero sugars is going to have a SG of less than 1. Ciders fermented with high attenuating champagne yeast will finish very dry-like 0.990. Read here:

How to Brew - By John Palmer - Yeast Terminology

My 1.061 Belgian Pale Ale got down to 1.009 at 6 days and still bubbled for a couple more... I'll be checking it tonight. It was mashed at 148 and oxygenated before I pitched the yeast. It took off like a rocketship. Those low mash temps make for a really fermentable wort!

moti_mo said:

Are you 100% sure that your hydrometer is calibrated correctly? It seems a little unlikely for a beer that big to ferment down to the density of pure water.

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I am absolutely sure that is correct. I tested it with water and came in at 1.000, and I used it with an APA that read 1.052, which was the target. Like I mentioned, that 100 %% AA is 81% real attenuation, so still very high. I'm assuming the low mash temperature, added simple sugars, and vigorous fermentation all combined for a super attenuation.

With 23% of your fermentables being simple sugars, I'm not too surprised. I've had braggots hit 100% apparent. You can calculate the real attenuation of the malts, but it's more work than it's worth IMO.

Yeah, I was trying to figure out how to calculate the real efficiency of the malt but it seemed to allude me. Anyhow, I'm pretty sure it's 15% as simple sugar, not 23%.

MacBruver said:

It's not that unlikely. There's a difference between "apparent" and "real" attenuation. Since ethanol has a lower specific gravity than water, 14% ABV beer with zero sugars is going to have a SG of less than 1.

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Definitely, I momentarily space that from time to time when figuring attenuation in my head. But...in my experience, I've never had a beer attenuate close to 1.00, I've had several in the 1.01 to 1.012 range, which I find to be pretty dry (I'm thinking of my 6 - 7.8% IPAs that I mash fairly low specifically to get them dry) but never one getting close to 1.00, even the ones I mash at 148.

Here's a question - ciders and the like aside - are there commercial examples, big beers or small beers, that have final gravities of ~1.00? I've looked up, or calculated, the FG values for a lot of my favorite beers, especially the big ones like Avery's Resolution, Maharaja, etc., and I haven't come across one with a FG of 1.00 or less. Just wondering...

The lowest I know of off the top of my head is Duvel, which finishes at 1.006. Anyhow, I recently made a IIPA (based off Pliny) that attenuated from 1.080 down to 1.010, and that's without any simple sugars, so I guess I've just had good luck getting high attenuation.

Upon further review, it appears Budvar's light lager has 104% apparent attenuation with an FG of 0.999. Miller Lite reportedly gets 100% AA for an FG of 0.999. The Pittsburgh brewing company has three beers that finish at 1.000. St Ide's Malt Liquor finishes at 1.004. Well this is certainly not a good list. I know mine tasted quite good in the sample, but hopefully it's as good when carbonated. My biggest concern is that the 35 IBUs in it will seem overly bitter considering the super-high attenuation.

I bet yours will taste great. The only one on that list of ultra-low-final-gravity you listed that I would drink is Budvar, the original version at least, I don't know if their light lager is different. But the original version on tap in Prague is actually not so horrible for what it is...