[jdibling]

Hey, all,

I made the switch over to AG after doing extract for a couple of years because it seemed like a fun thing to do, I got to buy more stuff, and I'd really like to make exactly the beer I (or my friends) want to drink.

So I'm doing BIAB, and I've done two batches so far. The first was a cream ale, which was delish, and the second was a hefe which just went in to primary yesterday.

Both times I was careful putting the recipes together, starting from another recipe with some very minor modifications. BeerSmith and Brewfather both told me what OG I was shooting for, and in both cases I missed it by about 25 points!

The first batch I figured I screwed something up in the mash. The temp got a little low to 140 for a few minutes, and then I overcorrected to about 160. It was at the correct mash temp for probably about 45 minutes. I also didn't ask my shop to double-mill the grains. But the second time I was much more careful with the mash temps and I was pretty much within 2 degrees of the mash temp for 60 minutes. And I asked for a double-mill and the grain I got back was pretty darned fine.  So I don't think that's what the problem was.

However it seems like I'm very consistently missing my gravity by 25 points or so. Any hunches what I might be doing wrong?

[denny]

When you use someone else's recipe you always need to adjust it to the efficiency of your own system.

[Megary]

Care to show us your last recipe?  25 points is a ton.

Like Denny said, if someone creates a recipe based on their brewhouse's 80% efficiency and you only get 70%...well you're doomed from the start.  As far as crush goes, even the double milling is probably still not fine enough for BIAB.  I can't say that for sure without seeing your grains, but it's probably the most likely cause for missing your predicted OG, if in fact you are missing it. For BIAB, the saying is "Crush til you're scared".  Well I wouldn't go that far, but you should definitely be feeling a bit uncomfortable. 

Also, how are you taking your gravity readings, and are you correcting for the sample temperature if need be?

[ynotbrusum]

Also calibration could be an issue as to temperature, volume, etc...which can throw you off.  A reliable Hand held instant read thermometer is a help, if not a necessity, even if you have a dial thermometer in your mash tun.  There can be hot spots and cold spots in a mash.  Too hot and enzymes degrade, too cold and enzymes react much slower.

[jdibling]

When you use someone else's recipe you always need to adjust it to the efficiency of your own system.

How do I figure out what my efficiency is? Just do a batch and measure?

The first batch I did, the mash efficiency was 54 percent according to brewfather. That seems just so low that I'm doing something wrong, doesn't it?

[jdibling]

Care to show us your last recipe?  25 points is a ton.

Like Denny said, if someone creates a recipe based on their brewhouse's 80% efficiency and you only get 70%...well you're doomed from the start.  As far as crush goes, even the double milling is probably still not fine enough for BIAB.  I can't say that for sure without seeing your grains, but it's probably the most likely cause for missing your predicted OG, if in fact you are missing it. For BIAB, the saying is "Crush til you're scared".  Well I wouldn't go that far, but you should definitely be feeling a bit uncomfortable. 

Also, how are you taking your gravity readings, and are you correcting for the sample temperature if need be?

Here's everything from brewfather, sorry for the verbosity

Vanilla Cream Ale - All grain
Cream Ale

4.9% / 12.2 °P

Recipe by
John Dibling

All Grain


5 Gal BIAB
64.2% efficiency

Batch Volume: 5.5 gal
Boil Time: 60 min


Mash Water: 8.76 gal

Total Water: 8.76 gal

Boil Volume: 7.75 gal

Pre-Boil Gravity: 1037


Vitals
Original Gravity: 1049

Final Gravity: 1012

IBU (Tinseth): 16

Color: 4.7 SRM


Mash
Strike Temp — 160 °F

Temperature — 155 °F — 60 min


Malts (10 lb 7.9 oz)
5 lb 0.1 oz (44.9%) — Briess Brewers Malt 2-Row — Grain — 1.9 °L
1 lb 14.3 oz (17%) — Briess Brewers Malt 6-Row — Grain — 1.9 °L — Mash
1 lb 14.3 oz (17%) — Briess Wheat White Malt — Grain — 2.3 °L — Mash
7.8 oz (4.4%) — Cara-Pils/Dextrine — Grain — 2 °L — Mash
7.8 oz (4.4%) — BestMalz Caramel Aromatic — Grain — 19.3 °L — Mash
7.8 oz (4.4%) — Briess Corn Yellow, Flaked — Grain — 1.5 °L — Mash
3.9 oz (2.2%) — Briess Barley, Flaked — Grain — 1.8 °L — Mash
Other (10.6 oz)
10.6 oz (5.9%) — Honey — Sugar — 1.3 °L — Boil — 10 min


Hops (1.27 oz)
0.44 oz (9 IBU) — Cascade 5.5% — Boil — 60 min

0.42 oz (5 IBU) — Cascade 5.5% — Boil — 20 min

0.42 oz (2 IBU) — Willamette 5.5% — Boil — 5 min


Hopstand at 170.6 °F


Miscs
0.833 items — Whirlfloc — Boil — 15 min

0.833 tsp — Yeast Nutrients — Boil — 15 min

1.667 oz — Vanilla Extract — Flameout

3.333 items — Vanilla Beans — Secondary

0.833 oz — Vanilla Extract — Bottling


Yeast
1.7 pkg — Omega OYL-044 Kolsch II 75%
Fermentation
Primary — 66 °F — 7 days


Carbonation: 2.4 CO2-vol

[Saccharomyces]

If I were you, I would stick with recipes that are basically base malt plus 10 to 15% colored and/or specially malts.  The bulk of the extract in any recipe comes from base malt; therefore, you need to know what you are getting from your base malt extract-wise.  Using potpourri grists like the recipe you posted is not doing yourself any favors.  The KISS (Keep It Simple, Stupid) principle applies to brewing.

[reverseapachemaster]

I agree the recipe is too busy but it's not why your efficiency is off.

The easy starting point is mentioned above--calibrating your tools. Are you sure your volume measurements were correct? The weight of the grain correct?

When you took preboil gravity readings did you cool the samples before testing or did you use a temperature correcting formula or tool? You could easily be far off on your readings if you read a 150F gravity sample and then guessed a little wrong on your preboil volume.

Depending upon how you were keeping the mash warm and how you checked temperatures you could have an issue there. If you were heating the mash on a low flame but checking temperatures at the top of the mash you could have had too much heat below which would denature enzymes and could lead to some issues with conversion, especially with all the adjuncts.

Otherwise the only ways I could see that being an accurate calculation of efficiency is if your grains were not fully mixed in the water at the start of the mash and you had some doughballs in there or you did a poor job pouring sparge water through the grain (but I'm guessing you know how to pour water and aim).

[dmtaylor]

I doubt the double crush was effective enough. Post a picture of the milled grist next time and we’ll tell you whether it is good or bad. You should see every kernel broken into 6 bits or so, with perhaps 10% of it becoming a fine flour, and no uncracked kernels. Nine times out of ten, the milling is the main problem.

If that ain’t it, and regardless, you also need to check the calibration of your mash thermometer in both boiling water and ice water, and check the calibration of your hydrometer in plain 60 to 70° water.  And check what the boiling point is at your elevation above sea level where you are located. It will be different from 212 F depending on your particular elevation.  (The freezing point fortunately is always 32 F regardless of elevation.)  Any errors on any of these variables could potentially have significant effects on your readings and help you to make adjustments on future batches using the same instruments.

[pete b]

I am apt to believe that there may have been measurement issues here. The original post states that the first beer came out good. I would think that there would have been obvious problems with the beer if the gravity was 25 points off. There could be efficiency problems too based on grain crush and mash temp. But maybe it’s only off by ten points.
Maybe you will be lucky and the next beer will be ok too. In the meantime, take the advice above and next time brew a simple recipe of a style you like. I recommend English ales if you like them, they are very simple, the og is modest, and if you don’t get it perfect they still come out pretty good. In fact, I would brew the same recipe 3 times in a row. Calibrate your hydrometer with distilled water at the temp listed as not needing correction per the hydrometer’s chart that comes with it, get a good quick read digital thermometer and check accuracy in ice water, and make sure your scale is accurate. Very good hydrometers, thermometers, and scales can be quite inexpensive. For now make sure the grain is crushed well, and just as  important, consistently. Make sure to cool gravity readings to very close to the hydrometer’s calibrated temp and use the chart if it’s a few degrees off to correct. Take careful notes and measurements and you can be confident in your efficiency when using recipes and recipe calculators.
If you feel like your enjoying making beer the next step is your own grain mill. They cost more than the measuring equipment but they are not bad either.

[narvin]

Crush is important, but making sure that the mash is completely hydrated and uniform also solves a lot of problems.  When I no-sparge I make sure to stir, stir, stir, and then stir again.  Your efficiency is already limited by the lack of a second rinse, so you have to make sure the water you use is as well mixed as it possibly can be and all grain is hydrated.  5 minutes of stirring at the beginning with a good mash paddle, a stir in the middle, and another at the end helps a lot.

[kramerog]

Crush and mixing like Narvin said.  A secondary thing is that I don't get as much extract out of flakes as I do base malts except for that time I preboiled my flakes.

[jdibling]

This has all been extraordinarily helpful input; thanks to all.

It's interesting to me that nobody has commented on the mash pH, which is what I was suspecting. I was simply using bottled spring water and did not measure ph or correct in any way. But that doesn't seem to be the tree everyone is barking up!

It's good advise to stick to a simpler recipe, and eliminate variables. I will do that for the next batch in a week or so and let you all know.

Regarding measurements and calibration, etc, I was using two thermometers. The kettle thermo built in at the bottom and a hand held instant read which I know for sure is precise and accurate. I also noticed variance from top to bottom, and frequently stirred to move heat around. No dougballs or anything like that.

I didn't actually weigh my grain, perhaps I should. I just trusted my local shop. But the last batch was crushed pretty fine. I'll take a pic next time.

The current batch is giving me some concerns with an ultra fast ferm, but that's a show for another day. Well see how it comes out.

Thanks again to all. This has been ultra helpful!

[jdibling]

Oh to answer the question how I'm taking gravity readings, two ways.

One is with a refractometer and letting beersmith do the conversions. The other is with a drawn sample and a hydrometer, which I leave storing on the table for a while until it cools.

Both readings cross referenced to each other fine - they both came up the same, within a point of each other.

[dmtaylor]

It's interesting to me that nobody has commented on the mash pH, which is what I was suspecting. I was simply using bottled spring water and did not measure ph or correct in any way. But that doesn't seem to be the tree everyone is barking up!

Great point, you may be on to something here with mash pH!  Sorry we missed it.  Yeah, with spring water, alkalinity often tends to be relatively high, and in a light colored beer like a cream ale especially, you'll probably need to acidify the water a bit to bring pH down to a more reasonable 5.6.  I would guess your mash pH was closer to 5.7-5.9, which yes is high.  Check mash pH next time for sure.