Hi all… it seems like no matter what yeast i use i keep getting attenuation of around 85%. I am on my 4th batch of the same NE IPA and i am looking to get a little more body out of it, but i cant seem to get the yeast to calm down! the beer tastes good so i know its not an infection.
i use an Anvil Foundry to do BIAB with a 1 gallon sparge. i have been mashing at 155-158 F for 60 minutes. grain bill is 2-row pale (80%), flaked oats, flaked wheat, carapils. i added some honey malt this last time too.
my crush is at 0.025, so i am thinking i need to increase that?
will mash thickness affect fermentability? i have seen cases for yes and no.
i have used 3 types of yeast, all with the same final attenuation, even though the mfg claims to be anywhere between 70-80%.
i dont check my pH but i use Brew n Water to calculate it to 5.4 ish.
Hops contain enzymes, so when you add a large dry hop charge like you normally would in a NEIPA, the hop enzymes will improve attenuation, beyond what you get from just the mash of the grains alone. Additional breakdown of sugars is happening during the fermentation. This is known as “hop creep”.
You might also be experiencing hideout from a diastaticus strain. But I think hop creep is probably the main thing going on. Which specific yeast strains have you been using?
Your crush is good at 0.025", I would not change that at all.
Mash thickness should not affect fermentability at all. This is another one of those old wives’ tales that just isn’t true.
Tell us your specific yeasts, and look into the hop creep phenomenon. Your answer is in there somewhere.
Wondering if you might be using a thermometer that’s out of calibration to measure mash temperature. That would explain consistently attenuating beyond expectations. Figuring ~1.25 gravity points/degree mash temperature, an error of a few degrees is all it would take.
This is a good point. I recommend calibrating your mash thermometer in both ice water at 32 F and at a hard rolling boil which is probably not right at 212 F as it changes due to elevation above sea level. You need to look up the boiling point for where you live. I know here for my thermometer, it reads a little high at one end and low at the other end, so at mash temperature it basically evens out and I can trust it. But most people are not so lucky with their mash thermometers.
for yeast i have used WLP 001, which i know has pretty high attenuation. WLP067 and Imperial A38 Juice. all gave me 83-85% attenuation. The A38 strain is listed as the lowest attenuation, so i was kind of disappointed when it came out so high. If there is a different strain to look into let me know.
as for temperature measurements, i have used 2 different calibrated thermocouples. both checked in ice bath and boiling water. they are dead on. i work at a test lab and we use high accuracy calibrated equipment, which i have borrowed to confirm my own equipment too. im only around 500 feet above sea level.
My hypothesis is that A38 Juice is a blended multi-strain yeast where most of it is lower attenuation, low 70s, while another portion of it is like WB-06 or the Lallemand New England strain which see average attenuation of about 82-83%. This would show up more and more upon subsequent pitches. If any of your brewing equipment has a place where this yeast can hide out, in scratches, or in rubber o-rings or hoses, or anything like that, you could be contaminating your brews with a high attenuating yeast like this. It’s happened to me and to many other brewers, unintentional yeast continuing to affect all subsequent batches. If this were true, then replacement of all plastic and rubber materials would eliminate the problem in future batches. I’ve had to do that too.
See here for an interesting thread on A38 which discusses this yeast as well as the impact of hop creep in NEIPA.
Or if you can get hold of a calibrated lab thermometer (I happen to have one that was calibrated right before I obtained it) you can use that to calibrate your mash thermometer at your mash temp.
Not sure about this. A brewer friend of mine also does full-volume (or nearly so) BIAB mashes, and his beers are also consistently overly attenuated, and they come across as dry and thin. He is doing everything right, and so I can’t help but think that full-volume BIAB mashes are causing this. If infection can be ruled out, then very high attenuation across different yeast strains means that you are consistently making worts with a LOT of fermentable sugars in them. So then we ask: what is happening in your mash that creates so much fermentable sugar?
The idea behind mash thickness affecting fermentability is feedback inhibition, where the product of an enzyme’s reactions inhibit the enzyme’s function. Feedback inhibition is built in to the biochemistry of all living things, including plant embryos. It’s a real thing in the mash. The question is whether it matters, i.e. makes a perceivable difference, amongst variable mash thickness levels. Within a “typical” range of mash thicknesses, probably not, and I think we can write it off as an old wives tale in that context.
But as the magnitude of a variable becomes more extreme, it is more likely to be noticed. With BIAB, mash thickness–or really, thinness–is taken to an extreme. In a thinner mash, there will be less feedback inhibition happening, perhaps enough to be noticeable.
At the mash temps you are using, you are favoring the activity of alpha-amylase. This enzyme cleaves the starches indiscriminately until all that’s left of the starch chains are limit dextrins. Although the conventional wisdom is that higher mash temps will result in less fermentable wort, it is possible that high alpha-amylase activity for 60 min combined with a thin wort (i.e. little feedback inhibition) is resulting in most of the starches and oligosaccharides being cleaved down to glucose and maltose. Hence, a very fermentable wort.
I doubt this issue is being caused by hop creep or other strains hiding out in your equipment. I suggest trying a more traditional liquor-to-grist ratio in your mash and see if that makes a difference.
As a BIAB’er I find this pretty interesting. But I have to ask at the risk of sounding stupid, if this were the case, wouldn’t all BIAB brewers have this problem?
I have experimented with different water:grist ratios and I have never encountered runaway attenuation (though I did get better conversion with thinner mashes).
You raise a very valid point…if it’s really an issue why do so many not experience it? I also agree that the only difference I saw with thinner mashes was slightly better efficiency.
In principle, yes, if they mashed at 158 for an hour with a very thin mash. But I don’t know many brewers who regularly mash at 158, and so a critical mass of observations may not exist.
I’m not convinced that what I’m suggesting is the case here. It’s just one possibility out of many. But this poster’s worts are apparently highly fermentable, which, assuming other possibilities are ruled out*, means that those worts have a sugar:dextrin ratio strongly tilted toward fermentable sugars. This points to a very high degree of enzymatic activity.
*and this admittedly is a big assumption and is not necessarily the case
great discussion. sounds like it may or may not be a bunch of different reasons! lol
any thoughts on mash pH? i am starting with distilled water and adding gypsum and CaCl to bring the pH down to 5.4 ish. this is calculated, not measured. 2:1 Cl:S ratio.
what about a shorter mash. i go 155-158 for 60 min then mash out at 170 for 10 min. if i am breaking down the long chain sugars too much would that decrease my fermentability?
i am 100% confident my temp is correct. i use all stainless fermenters and i clean and sanitize (two separate things) religiously.
sounds like mash thickness isnt a major factor, but i can thicken it up and see if it helps.
hop creep sounds interesting. i did charge it with 3oz mosaic on day 2 and 3oz mosaic on day 4.