Author Topic: low oxygen trappist  (Read 2697 times)

Offline homoeccentricus

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low oxygen trappist
« on: December 20, 2016, 09:23:26 PM »
Low oxygen Roach Four amber trappist enkel: preboil, smb and btb, mash cap, nosparge. Spunding in keg failed partially because of leak. Result: more than good enough to continue using this method. Maybe amount of esters could be better. The monks of Westmalle use shallow fermentation vessels to minimize the amount of CO2 in the fermenting beer, because apparently CO2 inhibits the formation of esters.
Frank P.

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Big Monk

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Re: low oxygen trappist
« Reply #1 on: December 20, 2016, 09:28:38 PM »
Awesome! I'm going to be playing with temperature and pitch rate to try and get a good ester profile.


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Offline homoeccentricus

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Re: low oxygen trappist
« Reply #2 on: December 20, 2016, 09:42:25 PM »
Serving temperature was 4C. Way too low. Will let the temperature rise and will try again tomorrow @10C or so.
Frank P.

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Big Monk

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Re: low oxygen trappist
« Reply #3 on: December 21, 2016, 02:52:57 AM »
Serving temperature was 4C. Way too low. Will let the temperature rise and will try again tomorrow @10C or so.

What recipe did you go with?

Offline homoeccentricus

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Re: low oxygen trappist
« Reply #4 on: December 21, 2016, 10:27:04 AM »
15 liter batch size

39 EBC
20.6 IBU
1.053 SG

79% pilsen
7.2% caramunich 3
4.3% flaked wheat
2.9% special b
6.6% candi 180
16 IBU Styrian Goldings @50
3.7 IBU Hallertauer Hersbrucker @25
0.5 IBU Hallertauer Hersbrucker @5
4 grams coriander
Belgian Abbey II (Wyeast Labs #1762)
usual amount of BTB in mash and boil
Hochkurz mash, nosparge.

Fermentation starting @17C, let rise to 24C
Frank P.

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Big Monk

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low oxygen trappist
« Reply #5 on: December 21, 2016, 11:10:45 AM »
Maybe you started too fermentation too low. If you take BLAM as a reference like I typically do (among other concurrent references), Rochefort starts fermentation a little higher.

What was your pitch rate? That's another thing that will inhibit esters.

I have been deciding on the right balance point using Chapter 8 from BLAM as a guide:

Key Points:

1.) Ester production is inversely related to yeast growth (more growth = less esters)

2.) Higher gravity = more esters

3.) Higher attenuation = more esters

4.) Fusels increase perception of banana esters

5.) Higher fermentation temp = increased ethyl acetate (solventy), floral and fruity esters

6.) Lower fermentation temp = inhibits esters and promotes phenol perception

7.) Higher pitch rates = lower ethyl acetate

8.) Lower pitching rates = more esters

9.) Horizontal tanks = increased esters

10.) Open fermentation = lower esters

11.) Cylidro-conical tanks = lower esters


The thing I'm looking to do is maximize pitch rate, temp and gravity to get the right ester profile and inhibit sediment left in the bottle when I bottle spund.
« Last Edit: December 21, 2016, 01:18:05 PM by Big Monk »

Offline homoeccentricus

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Re: low oxygen trappist
« Reply #6 on: December 21, 2016, 02:44:41 PM »
I think pitch rate was high enough. 15 liters, shaken-not-stirred 750 cc pitched at high kraeusen.

I made the Rochefort 4 once before, fermented at 18C and submitted it to a competition. The judge said he tasted isoamyl acetate, which should not be prominent in Rochefort, so  this time I lowered the temp a bit.

I also ferment in a keg. That doesn't seem to be ideal for esters.
Frank P.

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Offline Todd H.

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Re: low oxygen trappist
« Reply #7 on: December 21, 2016, 03:04:57 PM »

1.) Ester production is inversely related to yeast growth (more growth = less esters)

8.) Lower pitching rates = more esters


Just noticed that these two points seem to contradict each other.

Big Monk

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Re: low oxygen trappist
« Reply #8 on: December 21, 2016, 03:09:11 PM »

1.) Ester production is inversely related to yeast growth (more growth = less esters)

8.) Lower pitching rates = more esters


Just noticed that these two points seem to contradict each other.

True. I summarize the chapter pretty quickly this morning and may have fat fingered that one. I'll review and correct if needed.

Offline narcout

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Re: low oxygen trappist
« Reply #9 on: December 21, 2016, 03:56:20 PM »
I think pitch rate was high enough. 15 liters, shaken-not-stirred 750 cc pitched at high kraeusen.

I made the Rochefort 4 once before, fermented at 18C and submitted it to a competition. The judge said he tasted isoamyl acetate, which should not be prominent in Rochefort, so  this time I lowered the temp a bit.

I also ferment in a keg. That doesn't seem to be ideal for esters.

If you haven't read it before, there is some interesting information on ester formation here:

https://www.experimentalbrew.com/blogs/saccharomyces/have-you-seen-ester
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Offline erockrph

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Re: low oxygen trappist
« Reply #10 on: December 22, 2016, 08:47:58 AM »
I think pitch rate was high enough. 15 liters, shaken-not-stirred 750 cc pitched at high kraeusen.

I made the Rochefort 4 once before, fermented at 18C and submitted it to a competition. The judge said he tasted isoamyl acetate, which should not be prominent in Rochefort, so  this time I lowered the temp a bit.

I also ferment in a keg. That doesn't seem to be ideal for esters.

If you haven't read it before, there is some interesting information on ester formation here:

https://www.experimentalbrew.com/blogs/saccharomyces/have-you-seen-ester

I just reread this article for the first time in a long time, and this little nugget jumped out at me:

Quote
Finally, the type of sugar being metabolized plays an important role in the creation of higher alcohols, which, in turn, plays a role in ester production. Sucrose and fructose result in increased higher alcohol production, and so does glucose to an extent. Maltose metabolism results in considerably lower higher alcohol production than does glucose and fructose.

I wonder if this means that the simple sugars that are typically added by Belgian brewers tend to enhance the typical ester profile we get from Belgian ales. Of course, elsewhere in the article he mentions that a higher C:N ratio (sugar additions would increase this) tends to lower ester production, so maybe those factors cancel out. Still, food for thought...
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Offline homoeccentricus

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Re: low oxygen trappist
« Reply #11 on: December 22, 2016, 09:05:21 AM »
Yes, I think you are right. A Rochefort 8 would have at least 10% of candi sugar, my lower gravity version has only 6%.
Frank P.

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Big Monk

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Re: low oxygen trappist
« Reply #12 on: December 22, 2016, 09:55:11 AM »
The fact that beers with a higher portion of simple sugar also attenuate more plays into what Mark said in his article. Need to reread that today.


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Offline Phil_M

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Re: low oxygen trappist
« Reply #13 on: December 22, 2016, 11:49:27 AM »
That also has implications for us using invert syrup in our British Ales.

Maybe that's why I'm finding more beers "too clean".
Corn is a fine adjunct in beer.

And don't buy stale beer.

Big Monk

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Re: low oxygen trappist
« Reply #14 on: December 22, 2016, 01:38:17 PM »
I think pitch rate was high enough. 15 liters, shaken-not-stirred 750 cc pitched at high kraeusen.

I made the Rochefort 4 once before, fermented at 18C and submitted it to a competition. The judge said he tasted isoamyl acetate, which should not be prominent in Rochefort, so  this time I lowered the temp a bit.

I also ferment in a keg. That doesn't seem to be ideal for esters.

If you haven't read it before, there is some interesting information on ester formation here:

https://www.experimentalbrew.com/blogs/saccharomyces/have-you-seen-ester

I just reread this article for the first time in a long time, and this little nugget jumped out at me:

Quote
Finally, the type of sugar being metabolized plays an important role in the creation of higher alcohols, which, in turn, plays a role in ester production. Sucrose and fructose result in increased higher alcohol production, and so does glucose to an extent. Maltose metabolism results in considerably lower higher alcohol production than does glucose and fructose.

I wonder if this means that the simple sugars that are typically added by Belgian brewers tend to enhance the typical ester profile we get from Belgian ales. Of course, elsewhere in the article he mentions that a higher C:N ratio (sugar additions would increase this) tends to lower ester production, so maybe those factors cancel out. Still, food for thought...

I think a big driver would be that many of the Monastic Belgian beers are higher gravity (promotes more esters) and attenuate well (promotes more esters) due to higher portions of simple sugar as fermentables.