longer boil, missing OG by many points
hi all, i recently completed my first 90 min boil, with a scottish ale, as detailed in the recipe advice thread.
the predicted og at 70% was 1.063, and i ended up with 1.057 and thus missed my points by 6! now it was a 90 min boil, and with my 60 min boil i normally only miss it if any by maybe 1-2 points, why the big difference in OG for a longerboil?
And will this affect the final product? (apart from the abv of course) I was expecting an OG of 1.018 with my high 68 degree mash, and the specialties in place with english burton MJ yeast.
Anything I should be aware of?
Replies to This Discussion
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Permalink Reply by Peter Smith on
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Since I got my own mill I crush a lot finer then local shop. My mash looks more like THICK porridge now then say thin porridge. I think the finer mash cause the grain bed to be less porous during sprage and hence higher efficiency as the zero gravity sparge water has longer to extract sugars from grains. I now find Beersmith is spot on, before I have to add an extra 10% to all malts to hit numbers... I do the initial mash for 1hr 15mins then the sparge takes around another 45-60mins. It all changed when I got my own mill. I have a $200 barley crusher 2 roller with electric drill driving it. Allows me to now buy whole bags of grain so has already paid for itself.
Next time you mash write down the gravity after first mash but before sparge then again after all sparging but pre boil... I always monitor my gravities as sparging to make sure number make gut feel sense. In general I can go from 1.050 to 1.060 during a 90 min boil of 46L. if my pre boil is slighty low you can reduce bittering hops a bit...assuming beer will not be as sweat and may finish lower then planned. As a rule I DO NOT add sugar to make up gravity as I dont yet fully understand how this will effect the final taste .
Have hit 1.070 on a 46L batch , which is highest so far, I would have trouble getting more grain into my system anyways.
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Permalink Reply by Crusader-Rob on
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3hours! Now thats some time.
We did the istout clone a few months back, asa group collab, and that was 2 hours as it was.
Yeah it seems the BIAB Longer boils without sparging decreases the efficiency, The easy solutions is to add more grain to compensate for the drop in efficiency, the more in depth option, would be to carry out a sparge step. until I get a recrirc going....
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for the sparge to be effective you need a decent grain bed depth so the water has time to extract the remaining sugars, just pouring water through the bag slightly works but if you are trying to do a high gravity beer may disappoint if the water cascades through, as it will have very low sugar and dilute your main mash gravity. I will post a picture of my setup which when combined with fine mill size works well. If you bought a cheap 2nd pot and drilled the bottom yourself you could add to most setups for $50....
http://www.forum.realbeer.co.nz/photo/dsc01410?context=user
I lift the inner pot out and place an old fridge tray (metal type one) between pots, then simply pour the sparge water across the top, the key is a fine mill to produce about 1.5L per min run through... since doing this I have had to seriously revise all my BIAB recipes back to normal mash tun grain ammounts.
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Permalink Reply by Richard Rice on
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That's brilliant! So, both those pots are separate to the boil kettle? Do you mash in a different pot/kettle first, then transfer your grain bag to this set up or am I missing something? I'm keen to look into this some more.
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no the outer pot is the boil kettle, the inner one has the bottom laser cut like a mash tun false bottom. so you do your normal BIAB method inside the inner pot, water is in both pots at this time. Then lift inner pot out and place the grate between pots and sparge away. Also means you can give the mash tun a flash of heat during mash..
my oputer pot is 50L so this works better in 46L batches, basically I put 42L water into the system heat till I get 72C ish mash in, wait 75 min (I stir 3 times during this and sometimes lift inner partially out and lower back in so I get highest gravity I can) then liftout and start sparge. at this point I normally have about 25-26L in boil pot (with say 11-12kg grains in bag due to double batch), sparge drips through about 1.5L per min.
cheap way of doing sparge brewing BUT due to no recirc wort not crystal clear, I could recirc initial wort into pot then sparge I guess...
I have a series of photos from sundays spellbinder brewup, will post tonight.
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AWESOME! That looks like an ideal goal for the future! Love it, thanks for posting!
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Thats a nice looking swetup peter. good work.
Nice looking spellbinder brew mate, love that recipe...
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Permalink Reply by Ralph on
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I have been thinking along the same lines, but was hoping to get a fine enough mesh in the bottom that I would not have to use a bag at all...
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very doable imho, you would just have to have fine laser cuts, a recircle pump would be great as well for wort clarity, but I know Ralph that you dont rate this too highly, must say that my last few brews have been cloudy but great.... I have keg system now and learning about co2 carbonation and patience..... beer is actually clearing nicely in the keg. Last nights brew I put a little more koppa in at 15min rather then 10 and got stunning clear wort, I could clearly see the tip of the auto syphon 8inch under surface...
If you are going to go down this path, I would suggest making something to Prop the pot on the burner while sparging, I use 2 bits of 4x2 with decent burn marks on them as I fire burner while sparging to move time along.. I have never had an accident but it could tip over, I keep kids away from it etc just in case. Also you really need help to put the grill in while you hold the pot, alternatively you can put pot on ground after most water is out, place grate yourself and then stack, only losing maybe 500ml of liquid if you are quick and patient.
Did a saison last night (while drinking a few duponts for spiritual guidance and yeast harvesting) with 7kg pilsner and 2kg wheat, got 40L of 1.054 gravity wort so BS is telling me 75% efficiency I think.....still trying to figure it out... I could never get this doing single batches or using LHBS mill, my grist is way more floury... also if single batch there is not enough depth in the grain bed and the sparge water flush through too quickly , effectively diluting your first batch sparge. This batch got 3711, once my dupont starter grows up will redo with that but this time go a little more noble hop. Plan is to brett 1/2 of each batch.
The spellbinder was sunday afternoons work, gave 1/2 batch to a guy at work, already dry hopped it and keg it day before xmas...
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I am thinking fine SS mesh rather than laser cutting...
Rather than sitting it on a rack I already have a block and tackle system from a rafter and simply tie off when the lifted bag (or pot) is at the right height to drain.
I already have a setup which can recirculate. If I had a mesh bottom pot instead of a bag I think I would be recirculating to get uniform temperature and extraction of wort. If it gives clearer wort then that is a bonus, but I do not think you have to have clear wort going into a fermentor to get good clear beer out of a fermentor...
Kegs are great! Soo much easier than bottling once it is all sorted out.
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