Not hitting my OG

[Tehee2000]

Good evening everyone.

I've been an avid reader of these forums for a while, but have until now i've never posted.

I'm struggling with my All Grain set up to achieve the OG for the beers I am brewing. Last night I brewed a Bishops Finger from Clone Brews 2nd Edition. The OG in the book drops in the range of 1.052-53, mine came in at 10.42 .

I used Beersmith to scale my recipe and the grain bill came out as follows.

5 Gal Batch
3.96kg Maris Otter
0.54kg Flaked Maize
0.27kg Rice Hulls
0.44kg Crystal 60
0.41kg Torrified Wheat
0.14kg Amber Malt

According to Beersmith this should equate to a SG of 1.053 (assuming 70% efficiency I believe)

Here are the readings I took throughout the brew session.

I mashed for 90 mins (17.5L Water) @ 66.7. My Mash tun held @ 66c for over an hour before finally dropping to 65c at the end of 90 mins.

First Runnings = 1.080 @ 20c

I Batch Sparged 28.11L @ 75.6c

2nd Runnings = 1.020 @ 20c

Collected a total of 39L of wort (Beersmith reckons my boil volume should be 37.36L) ### MORE ON THIS BELOW ###

Boiled for 90 mins with my hop additions, cooled and transfered to Carboy.


My set up is as follows
MASH TUN - Cool box with copper pipe filter system (2.5L Dead Space)
HLT/KETTLE - 50L Pan converted with Tap and Filter (5L Dead Space (Yes I know this is a lot but the tap is not exactly near the bottom )

As I mentioned before My Dead space in my kettle is 5L, I achieved 39L of Wort, which in effect is only 34L. This is where I am getting confused. When it states PRE BOIL Volume of 37.36L is this a Total volume or in my case should it be 37.36L + the 5L for my dead space in my Kettle? Even after boiling for 90 mins I still had a couple of litres (if not more) left above the tap on my Kettle once the carboy was full, plus the 5L of dead space.

Don't get me wrong the beers i've made in the past have tasted great, but the OG is continually dropping below expectations every time and its finally time I addressed this by asking for advice from people far more well versed in this than myself.

Feel free to be honest and brutal, this issue needs resolving.

Thanks in Advance

Terry

[Eadweard]

I found slowing down the sparge increases extract efficiency, as does getting the liquor treatment right.

[Tehee2000]

Thanks for your reply Eadweard,

How long would you call a slow sparge? I'm sure I could definately slow mine down. I did end up with a stuck sparge with this beer, so mixed it up and recirculated some wort (this was during the 2nd runnings)

Secondlly what is meant when you refer to liquor treatment?

Thanks

[Matt in Birdham]

I think there are two general issues here. The first is that you have too much pre-boil volume, and the second is that your boil-off rate is likely set too high within BS, and you are not reducing the wort volume by as much as you need to.

I too always get more pre-boil wort than BS suggests, and have adjusted accordingly. One reason for this (in my case, at least) is that BS always gives volume measurements for the step temperature. E.g. if you need to mash in with 17.5l of water, then this is 17.5l at strike temp (say, 72C). The volume difference between 72 and tap temperature isn't large, but it for the full amount of water it might amount to a litre or so so I do now adjust for that. Was your pre-boil gravity on target? That would be a useful data point.

Secondly, and probably more importantly, it looks like your boil-off is overstated within BS. If you took pre-boil and post-boil volume measurements then you should be able to determine your hourly boil-off rate and update BS accordingly. A 39 litre boil is massive for a 5 gallon (US, UK?) batch, even for a 90 minute boil. I did a 22l litre batch a few days ago which also had a 90 minute boil, and my pre-boil volume was 29 litres! I boil off about 4 litres an hour - you would need to boil off about 10 litres an hour to leave, say, 23 litres in your kettle and transfer 22 to your FV.

I don't get the issue with your kettle "dead space" either. 5 litres is a lot - why don't you just pick up your kettle and pour the rest in? If you are actually accounting for your deadspace, and trying to make 5 litres + 5 gallons of wort, then your grain bill looks a little light to me. Although admittedly I don't have a super efficient system (I full volume mash), I generally use about 5.25kg of grain to make a 5.5g batch of 1.053 wort. If this is the case, you may also need to look at adjusting your brewhouse efficiency downwards in BS.

[Tehee2000]

Thanks Matt,

Let me pick up on what I can easily answer first, and yes UK Gallons

Boil off - I lost 7 Litres in 90 mins (4.67l ph) It looks like BS has my boil off set to 5l ph, so maybe not a huge difference here.

My Pre-boil gravity is the only reading I dont have (the wife knocked it over as it was cooling) I will however strive to get this data on my next batch.

I take on board your volume comments regarding strike and tap temperature and I will calculate accordingly (something I had ont actually thought about before)

I'm glad you mentioned my Kettle. Yes 5l is a silly amount of dead space. I really should alter BS so that I can just tip the damn thing up. Do I just up BS Trub Loss to 0 (mines currently on 5L) This would increase my boil time too as i would be bringing 10L less to the boil.

I'm going to do another beer next week, taking into consideration your points and see if I can get my OG somewhere nearer where they should be. I definately think you are right with regards to Volume, and that is what i am going to look at.

Cheers Matt

[Fil]

the 7.5l deadspace in your vessels probably accounts for the drop in OG from the target, as the sugars that remain in the liquor in the pots isnt in your FV contributing to your brew, and its effecting your BHE Brew house efficiency.

Now you can account for this by adjusting the BHE in your app to reflect what your results are producing. your app is probably based on a 75% BHE where your efficiency is currently less.
Work out your efficiency from the last brew, using an online calculator http://www.brewersfriend.com/brewhouse-efficiency/ might be one in here too ??
and that should then adjust the recipes by upping the grain bill a bit for you..

Next when you have determined the boil off volume from your kettle during a 90 minute boil you will have all the info you need to hit both volume and gravity targets much closer if not bang on.

Lets use 4l as an example boil off durring a 90 minute boil for now.

so with an adjusted grain bill to reflect your BHE the volumes are easy to calculate.

1) Strike volume calculate solely on the mash consistency ignoring tun deadspace..

calculate your preboil target by adding 23l (target finished volume) + 5l deadspace +4l boil off
= 32l wanted from the mash/sparge.

2) so sparge volumes? well i would suggest rather than draining the tun 1st you instead fill the tun with your sparge liqour ontop of the mash to the brim, stir, and let sit for 25-30 mins, and then drain into a spare bucket that you can measure the volume in. and measure the runnings.

Calculate sparge #2 volume by subtracting sparge 1 runnings from your preboil target so if you want 32l and draw 18 litres from sparge #1 you need to simply add 16l (32-18) for the second batch as it will then run off 16l making your 32l.

[Eric]

Agree with all advice given, so just wish to add a few figures.

Assuming you get 11 litres of wort at 1080 from your drain down of the mash plus another 28 from your sparge at 1020 you will have extracted more than 70% of the potential sugars. By the method you use I think that would be as expected, but you should be aiming for more.

Leaving 7 litres out of 30 in the boiler is a 23% loss you can't afford. If tipping the boiler is all that is needed to solve the problem then fine, but otherwise you must somehow reduce that loss to say 2 litres and thereby reducing sparge liquor by that amount. This will in turn increase the need to improve your extraction efficiency.

A second sparge and sparging more slowly will increase extraction as suggested.

[Tehee2000]

Good evening chaps,

I've finally got around to doing another AG brew taking on a lot of the advice from you guys. Firstly I have elimated the 6L deadspace from my kettle, altered my boil off to 4L/ph and slowed down my batch sparge times

first runnings - 10L collected in 35 mins
2nd runnings - 18L collected in 50 mins.

From my research I concocted this Sierra Nevada Pale Ale Recipe

23L Batch

5kg Maris Otter Low Colour [2.5EBC]
0.7kg Crystal 60 [60EBC]
19.5g Magnum [10.9%aau] 60mins
25.0g Perle [3.9%aau] 30mins
17.0g Cascade [8.6%aau] 10mins
83.0g Cascade 0mins

Yeast Safale US-05 American

I carefully measured out my volumes. and mashed my grains in 17L of water @67C. This temp held for the full hour.

1st Runnings 10L @ 1.082
2nd Runnnings 18L @ 1.034 (I had to tilt the mash tun for the last half litre)

Total Preboil Vol = 28L (27.92 Expected according to Beer Smith)
Preboil OG = 1.048 (1.045 Expected according to Beer Smith)

Total Post Boil Vol = 22L (23L Expected according to Beer Smith)
Post Boil OG = 1.056 (1.054 Expected according to Beer Smith)

I did have a battle fishing the last litre out of my kettle from the hops, so maybe I should add an extra litre of water in at the sparging stage???

But as you can see, thanks to your help I have actually come in above the OG by a couple of points.

I'll let you know how it tastes. Its currently been in the primary for 4 days now and im considering racking it into secondary or just leaving it