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Message |
    
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 306
Registered: 06-2003
Posted From: 99.56.136.130
| | Posted on Thursday, October 29, 2009 - 10:42 pm: | 
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Can old grains cause poor efficiency and or attenuation? Any experience with this?
thanks.
mark
www.backyardbrewer.blogspot.com
wwwthebackyardbrewer.com |
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 307
Registered: 06-2003
Posted From: 99.56.136.130
| | Posted on Thursday, October 29, 2009 - 10:46 pm: |
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Along that same line, if the beer doesn't ferment out far enough (leaving a lot of sugar when done) will it still carbonate when you bottle normally?
mark
www.backyardbrewer.blogspot.com
www.thebackyardbrewer.com |
Bill Pierce
Moderator
Username: Billpierce
Post Number: 10880
Registered: 01-2002
Posted From: 24.141.103.148
| | Posted on Thursday, October 29, 2009 - 10:52 pm: |
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The short answer is no, but there are exceptions. For example, pre-crushed grains and flaked ingredients should be used within about 60 days, and grain stored in a wet environment could become moldy. Can you provide more information about the specific grains you are referring to?
The biggest factor in mash efficiency is the quality of the crush; as for attenuation, the major factors are the yeast strain and management (pitching rate, aeration, etc.), and the starch conversion temperature.
To answer your second question, it is occasionally possible for beer with a high F.G. to spontaneously referment later, causing bottle bombs. It depends on whether fermentation was interrupted earlier before it completed.
For beer not to naturally carbonate would require either that the yeast be dead or have exceeded its alcohol tolerance. Again, more information about your beer (style, O.G., F.G., yeast strain, size of starter, aeration method, etc.) would be helpful.
(Message edited by BillPierce on October 29, 2009) |
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 308
Registered: 06-2003
Posted From: 99.56.136.130
| | Posted on Friday, October 30, 2009 - 04:28 am: |
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This is a Belgian ale
21 lbs. pils malt with my typical crush in which I normaly get a 85% efficiency. Grain was mashed for 60 min. at 150f. and sparged with 170f. h2o. Beginning boil volume was 13gals. for 60min. with 6lbs. cane sugar. Original gravity was 1.078 and wort was pumped through aerator as it entered fermenter.
I pitched WLP570 yeast that I stepped up twice and krausen formed after 10 hours at 65f. Fermentation continued normally as I raised the temp into the high 70's over a period of 5 days. Krausen started to drop and I did a gravity check and it read 1.036 or 53% attenuation. 2 days later gravity dropped only .002 and little activity is evident.
The odd thing here is that I usually get 85% efficiency and that I usually have an attenuation near 80% on my ales. The only variable in this scenerio compared to my normal regimen is the fact that the pilsner malt was given to me from a friend and I keep the ferm. temp. constant at 65f. and it's not my normal 2-row malt.
Hope this helps.
mark
www.backyardbrewer.blogspot.com
www.thebackyardbrewer.com |
Bill Pierce
Moderator
Username: Billpierce
Post Number: 10881
Registered: 01-2002
Posted From: 72.14.171.58
| | Posted on Friday, October 30, 2009 - 03:48 pm: |
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I don't see anything terribly wrong with your efficiency. I'm assuming this is a 10 gallon batch. Efficiency drops off for higher gravity beers; it's difficult to rinse all the sugars from a high gravity mash without oversparging. While I achieve around 80 percent efficiency for lower gravity beers, it's more like 70 percent for bigger beers.
However, there is something wrong with your attenuation. Some Belgian breweries achieve as high as 90 percent apparent attenuation with worts that have a high percentage of brewing sugars. Homebrewers often have difficulty achieving such high results, but you should be able to hit around 80 percent with your beer.
Usually the fault lies in the yeast management. When you say you stepped up the yeast pack twice, what was the size of each step? I'm trying to determine how much yeast you actually pitched.
For my 10 gallon batches of Belgian strong ales, I will pitch the yeast sediment from a 2 gallon starter. If I start with a relatively fresh Activator (125 ml) smack pack, I will first make a 3 liter starter. If I'm using my own yeast sediment stored under distilled water, the first step will be about 500 ml, and then to 3 liters before the third and final step. I aerate the chilled wort with pure O2 via an inline aeration stone. My typical lag times are about 3 hours.
(Message edited by BillPierce on October 30, 2009) |
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 309
Registered: 06-2003
Posted From: 99.56.136.130
| | Posted on Friday, October 30, 2009 - 04:03 pm: |
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The first step is 1/2 cup dme in 900ml. several days later I will pour off the liquid from the yeast cake and add another (boiled and cooled)1/2 cup dme in 900ml. There is usually about 3/8" of yeast sediment in flask. |
Hophead
Senior Member
Username: Hophead
Post Number: 2881
Registered: 03-2002
Posted From: 167.4.1.41
| | Posted on Friday, October 30, 2009 - 04:11 pm: |
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I see no reason why flaked ingredients need to be used in 60 days, I've used them much later than that with no issues, and I guarantee that most homebrew shops have flaked maize/oats/barley/rye/etc on the shelf for FAR longer than 2 months. |
Tony Legge
Intermediate Member
Username: Boo_boo
Post Number: 473
Registered: 05-2005
Posted From: 174.116.59.12
| | Posted on Friday, October 30, 2009 - 09:26 pm: |
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I agree with Hophead. I have flaked maise in my basement in vacuum sealed bags, that have been there 4 months and the place from where I got it had it in plain plastic bags that they did themselves from sacks they imported.
I would estimate that the oxfam place I got them from didn't get it express delivered and I imagine it was shipped by boat. I also would venture to say, it took quite a while for it to get here under god knows what conditions.
And here in Nfld, a priority destination for grains and such, we aren't.
I still make great beer with it, but at the same time don't add a lot of maise to any recipie. The maise, when I open it, still smells good to me. |
Bill Pierce
Moderator
Username: Billpierce
Post Number: 10882
Registered: 01-2002
Posted From: 24.141.103.148
| | Posted on Friday, October 30, 2009 - 10:22 pm: |
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I stand corrected. According to Briess, flaked ingredients should be used within six months rather than 60 days. |
Dave Witt
Senior Member
Username: Davew
Post Number: 1354
Registered: 03-2003
Posted From: 68.57.245.38
| | Posted on Friday, October 30, 2009 - 10:44 pm: |
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Mark,
If you're using a Wyeast activator pack, you can go right to about a half gal, then after it ferments out, repeat or go a full gal for a bigger beer like that, so you know you have enough yeast. Use the Mr Malty yeast pitching calculator to find out what you need.
http://www.mrmalty.com/calc/calc.html
(Message edited by davew on October 30, 2009) |
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 310
Registered: 06-2003
Posted From: 76.254.70.33
| | Posted on Saturday, October 31, 2009 - 02:15 am: |
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Thanks Dave (and Bill),
I have to assume, based on info here that I just didn't pitch enough and will use the mrmalty calcs next time. The proceedure I outlined earlier has always worked for me but I guess the higher gravity of this beer was an exception. In the mean time for better or worse I added a couple packets of US05 to try and bring the gravity down. It seems to be working as the gravity has dropped another 6 points and a new kraeusen is forming. I'll just chalk this up to education and call it a hybrid style Belgian ale if anyone asks. Make it sound special, like I did it on purpose.
mark
www.backyardbrewer.blogspot.com
www.thebackyardbrewer.com |
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 311
Registered: 06-2003
Posted From: 99.56.138.191
| | Posted on Thursday, November 05, 2009 - 03:46 pm: |
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Just a quick info update here. The US05 yeast did indeed further attenuate the beer dropping the final gravity down to 1.015 (79%). Although this beer should finish in the 1.010 range I am happy that it got down as low as it has. I have bottled and kegged and look forward to seeing how the bottled beer carbonates. I added a carbonation drop to each 12oz. bottle.
mark
www.backyardbrewer.blogspot.com
www.thebackyardbrewer.com |
Bill Pierce
Moderator
Username: Billpierce
Post Number: 10895
Registered: 01-2002
Posted From: 24.141.103.148
| | Posted on Thursday, November 05, 2009 - 04:21 pm: |
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Among the most difficult tasks for the homebrewer is to achieve the high attenuation of Belgian commercial breweries. This requires mashing for a highly attenuative wort, using a significant percentage of sugar in the recipe, very careful yeast management practices (high pitching rates, extensive aeration), and warm fermentation temperatures. Considering what you did, I wouldn't be too upset with 79 percent apparent attenuation. The beer should certainly be drinkable, and you have some idea of what to do next time to improve it.
(Message edited by BillPierce on November 05, 2009) |
mark taylor
Intermediate Member
Username: Marktaylo
Post Number: 312
Registered: 06-2003
Posted From: 99.56.138.191
| | Posted on Thursday, November 05, 2009 - 05:02 pm: |
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Yes, a good learning experience and I take it as a challenge for the next batch. In the mean time, I see that the beers are carbonating in the bottle based on the small kraeusen that has appeared at the top of the fill.
mark
www.backyardbrewer.blogspot.com
www.thebackyardbrewer.com |
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