We’ve noticed (and perhaps you have too) that the level of spice on the JIIPA varies dramatically, with some batches only having jalapeño on the nose and others being overpoweringly spicy. We’ve aimed to resolve this issue by making a jalapeño tincture that can be used to titrate spice into the beer until we hit the correct level. Below is the experimental outline, results, and some photos.
Above: making the tincture
For the tincture: 1kg fresh jalapeños with seeds, quartered; 2L grain alcohol (75.5% ethanol). Cost: ~$60.
Preliminary: The main spicy compound in peppers is called capsaicin, and it occurs in greater amounts in spicier peppers. While we could certainly have more economically isolated more capsaicin by using stronger (eg habanero) peppers, we opted for jalapeños for the following reasons: any additional flavor compounds from these peppers would be less likely to be detectable in the final beer; additional spicy compounds (capsaicinoids) may occur in degrees specific to each pepper variety, and if this is the case, using jalapeños allows us to preserve any specificity in jalapeño-esque spice.
Our method: After mixing the tincture, the ethanol was noticeably green and by 1 week the jalapeños had lost significant color. Ethanol was then drained from jalapeños, jalapeños were discarded, and ethanol was allowed to evaporate for two days, until volume reached 1.5L (further evaporation is certainly possible). Assuming only ethanol evaporated, the final alcohol concentration of the tincture is 66%. At this point the tincture was dark and aromatic. Evaporation could be sped up (dangerously) on the stove top.
Test: Spice is generally measured with scoville testing. To do this, make serial dilutions of your stock. The first (weakest) dilution at which you can detect spice is the scoville rating. For example, if you can taste spice at 1:5000 but not 1:6000, your stock was at ~5000 scoville units. Note that scoville ratings on peppers are generally performed with dried peppers, in an oil extract, and aim to define a rating within 100 units. For our purposes, generating a rating for our tincture is sufficient. Not a perfect test, obviously, but workable. For our scoville testing, we used a boiled 1.015 wort for our serial dilutions, the same gravity as the JIIPA after fermentation.
Result: our tasting panel put the scoville rating of the tincture at around 7500. We generally aim for 75 to 100 on the JIIPA, which for a 5g batch is 200ml of tincture. After carbonation, it was clear that had hit the mark head on, but we tested anyway and hit ~75. No additional alcohol was detectable, although 200mL of tincture should bring the beer from 8% to 8.62%.
Future: This batch of jalapeños was not particularly spicy, but $60 worth of ingredients was still enough to spice 37.5g of beer, so we’re in a workable range. In the future, multiple rounds of peppers could be extracted in one batch, and more alcohol could be evaporated, such that we will not significantly change the ABV of the beer by tincture addition.
Above: the final tincture